Category Archives: Research

A Mite-y Big Problem at Flycatcher Nest

I dislike unhappy stories and enjoy writing about them even less. However, I have to remind myself that not everything is about the birds — Mother Nature is a much more clever scriptwriter than that.

I mentioned in my last post that there were some moving specks on the vinyl siding behind the nest that I suspected might be some kind of bird mite. Here is what my research found.

At the end I share my opinions as to the effect that the mites had on the nestling development and their departure from the nest.

Visual Evidence of Mites

I went back and looked at video footage to look for evidence of moving specks which I would later confirm to be mites. It turns out that a good way to see them is to fast-forward the video and watch closely — the mites are easy to see when moving, especially those on the light coloured vinyl siding.

I found the first mite evidence in the July 19 webcam footage — (hatch-day + 8). On subsequent days, the quantity of mites increasing dramatically, dare I say ‘exponentially’, until the three nestlings left the nest on July 23. While the initial mites were only seen while moving on the vinyl siding, by July 21 large immobile clusters of mites could be seen on the outdoor light fixture. Here is a picture taken on July 22 with my Panasonic FX-200 camera:

Mites grouping on the outdoor light fixture.

The out-of-focus mites are still visible on the siding behind the nest. More obvious are the the brown patches on the black edge of the light fixture in which individual mites are easily visible. The reddish-brown colour comes from mites that have all taken some blood, probably from one of the nestlings (’empty’ unfed mites are light coloured).

To study the mites more closely, I ran a lint roller along the edge of the light fixture. This was surprisingly effective at removing all of the mites in its path. The sticky lint-roller paper immobilized most of the mites however there were still a number of wandering mites so I sprayed the sample with a mixture of bleach and water to make sure the mites were dead before the sample came into the house.

To demonstrate the mite size and numbers, I took a picture showing a section of lint-roller paper with mites next to a Canadian dime:

Mite sample acquired using a lint roller.

A dime is about 1.8 cm in diameter so I estimate the density of mites in the high-density area along the top of the sample to be about 200 per square centimetre. After the nestlings had left the nest, there was extensive coverage of the light as well as 4 or 5 patches of packed mites on the siding. Estimating the visible coverage at around 200 square centimetres that would mean about 40,000 mites. This is just the visible areas and the hidden areas on the light fixture. Any mites on the nest or the nestlings are not included though one might expect both to be heavily infected. My best estimate for the total mite count is somewhere between 50,000 and over 100,000.

We have a Wild M11 microscope which I used to get a better look at the mites. Using my iPhone camera, I was able to take some surprisingly good pictures. The following image was taken at the lowest (4X) magnification:

The wire has a length of about 2.2 mm at this magnification (calibrated with a plastic ruler) making the mites’ length about 0.6 mm. The next image was made at the next highest magnification (10X). Unfed mites are clear so this looks like a mite that has fed on blood — nestling blood most likely.

Identification

The two most common North American bird mites are the Northern Fowl Mite (Ornithonyssus sylviarum) and the Chicken Mite (Dermanyssus gallinae) which goes by several other names such as the Red Mite, Red Fowl Mite and Red Poultry Mite. Both are of great interest to the poultry industry because of the costly damage they can do. Both can infect wild bird species. From various sources I have read, I concluded that the flycatcher nest was probably infected with the Northern Fowl Mite.

The best reference that I found summarizing issues around bird mites and humans comes from a 2010 document from the PennState, Department of Entomology series of short Entomological Notes simply titled BIRD MITES (accessed July 28, 2017). Below, I quote a few of the more relevant paragraphs and highlight important sections that helped me handle the flycatcher mite infestation:

Bird mites are very tiny, flattened parasitic arthropods in the order Acari. They belong to two closely related genera in two families; Dermanyssus species in Dermanyssidae (Fig. 1), and Ornithonyssus species in Macronyssidae. Bird mites have piercing mouthparts that enable them to take blood meals from their bird hosts. Although the mites will inadvertently bite people, they cannot reproduce without their bird hosts.

DESCRIPTION

Bird mites have five stages: egg, larva, protonymph, deutonymph and adult. The larvae have three pair of legs; the nymphs and adults have four pair. Adults are about 0.7 to 1 mm in length and are just barely visible to the naked eye. Unless they are moving, they are extremely difficult to see. The color is translucent white until they take a blood meal after which the mites are reddish mahogany to brown. Mite eggs are white, oval and cannot be seen without the aid of magnification. The same applies to the larvae and nymphs.

LIFE HISTORY/BEHAVIOR

Most bird mite species can complete development in five to twelve days with optimal temperatures and host presence. This short life cycle makes it is possible for mite populations to attain tens of thousands of mites in bird nests during the rearing of young birds. If the population is too large (or if the fledglings vacate the nest or perish), the mites will migrate in mass to locate an alternative host. It is during this migration that mites can and do enter the living quarters of people. Some mites (i.e. Dermanyssus gallinae, the chicken mite) can survive for several months without taking a blood meal; the northern fowl mite, Ornithonyssus sylviarum, for several weeks. However, the mites do not appear to survive for more than several days in the reduced humidity (<35%) environs typically found in air-conditioned or dehumidified homes.

…

MANAGEMENT

Birds should be discouraged from building nests in or adjacent to buildings. Close all openings large enough for birds to enter attics, sof ts and similar areas. Install hardware cloth, sheet metal, or other materials to prevent birds from nesting and roosting on porches, breezeways and other exterior sites. Disrupt nest-building efforts by removing partially completed nests in shrubbery and on air conditioners and windowsills.

If mites are detected in the structure, locate the bird nest source. Remove the nest.

…

My take home message was to monitor the mites both around and away from the nest and be prepared to remove the nest and sanitize the nest area once the nestlings had left the nest to prevent the host-less mites from moving inside the house looking for new targets. I read some accounts of the problems that resulted from houses that became infected by bird mites (readily available on the websites of many extermination companies) and they definitely made me want to keep the mites outside.

Of Mites and Nestlings

Beside the visual evidence of an exploding mite population, the nestlings became increasingly restless as the quantity of mites increased. Frequent episodes of scratching were noticeable on the webcam videos.

My personal belief is that the nestlings left the nest early, before the were ready to fledge, in large part because of their discomfort from the mites. I know that one nestling perished because I found the body on the morning of July 24. The last sighting of a nestling was on the morning of July 25. The last sighting of the female adult sticking close to its foraging area near our house was on July 25.

One final reason why I do not think that there were any surviving nestlings was the presence of a domestic cat nearby. The day that I found the dead nestling, it was lying in our driveway when I returned home from some errands. I have seen the cat, before and since, in and around our yard. An unfledged nestling hopping in the bushes would have had little chance of avoiding the feline if it were spotted.

References

I have listed below some of the interesting references that I found online.

[1] This 2005 reference contains some good high-level information on mites: Common Lice and Mites of Poultry: Identification and Treatment.

[2] One of the best short summaries on bird mites that I have found: UW Madison Department of Entomology information sheet.

[3] Good reference from Iowa State University: Bird-Mites.

[4] A good 2014 review article: Mites and birds: diversity, parasitism and coevolution.

[5] A 2014 research article looking at some of the relationships between birds and mites: Repeatability of Feather Mite Prevalence and Intensity in Passerine Birds.

[6] Slides from a presentation showing the Poultry Industry’s views on Northern Fowl Mites.

[7] Washington State University research proposal and status: ORIGIN AND SPREAD OF THE NORTHERN FOWL MITE: A LANDSCAPE GENETICS APPROACH.

[8] Google Books textbook chapter: Global Diversity of Mites.

[9] Countryside Daily article with some information that I did not find elsewhere: Chicken Mites & Northern Fowl Mites: Controlling Infestations.

Watching Coot-Looting Wigeons at Buttertubs Marsh

References

A good source of information that I like to use is the Birds of North America online service from the Cornell Lab of Ornithology. The service is not free but for anyone curious about bird behaviour it’s worth the price in my opinion. They have a one month subscription that costs $5 if you want to give it a try.

[1] BNA online article on the American Wigeon.

[2] BNA online article on the American Coot.

[3] H. Jane Brockmann & C. J. Barnard, Kleptoparasitism in birds, Animal Behaviour Research Group, Department of Zoology, University of Oxford, UK
Animal Behaviour (Impact Factor: 3.14). 05/1979; 27:487-514. DOI: 10.1016/0003-3472(79)90185-4

[4] Juan A. Amat & Ramón C. Soriguer, Kleptoparasitism of Coots by Gadwalls, Ornis Scandinavica 15: 188-194. Copenhagen 1984.

Watching a Family of Palila on the Big Island

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[Updated December 10 2014 based on feedback. Additional links on the Palila have been added.]

A recent week-long vacation took us to the Hawaiian Islands (October 26 to November 1). Having previously been to the island of Kauai at the old end of the island chain, we decided to try the island of Hawaii at the other, newer end. To prevent confusion with the state of Hawaii this is frequently referred to simply as the Big Island. I had my Panasonic FZ-200 camera along to document the trip.

On the last full day, I signed up for a Rainforest and Dryforest Birding Adventure tour — a day-long outing put on by a tour group called Hawaii Forest and Trail. They do many other tours too that are not just for birding. The rest of our group, for instance, went on the Mauna Kea Summit and Stars Adventure trip which takes you up to the volcano’s summit to watch a sunset.

Our trip set out in search of 2 specific target birds. In the dry forests on the side of Mauna Kea we would be looking for the Palila, a critically endangered species which lives in a single forested area on the volcano’s slopes. This forested area is the source of the māmane plant which the Palila has adapted to be able to eat and which is toxic to other birds.

In the second part of our excursion, we would travel to some wetter forests where we hoped to find different endemic, the ʻAkiapōlāʻau.

While we were, unfortunately, unable to track down the ʻAkiapōlāʻau, we were extremely successful with the Palila and the rest of this article describes that encounter.

Mauna Kea and the Palila

First, a quick note and the Palila habitat on the slopes of Mauna Kea.

Mauna Kea is still considered to be an active, though dormant, volcano and even though it has not erupted in 4600 years there is still the slim possibility that a lava flow from a future eruption could wipe out this habitat leading to their extinction. While this might make for a good story in Hollywood, the reality is that there are much more dangerous risks that could well see the Palila gone from these slopes long before they are touched by lava. Forest fires, for instance could, in the right conditions, very quickly destroy the Palila habitat. Other threats include introduced species of plants, animals, insects and disease. The Hawaiian government’s Mauna Kea Forest Restoration Project has lots of good information here. Finally, according to BirdLife International, the endangered status of the Palila in recent years is also related to rapid population declines as a result of drought that has affected its primary source of food, the māmane plant.

The Palila Plan

The plan was simple. We parked in an area accessed by a hunter access road on the lower slopes of Mauna Kea. The trip organizers allowed for up to 4 hours climbing the slopes to find and view the Palila after which time, win or lose, we would head for the second location.

Here is a picture taken near our parking spot and at the lower edge of the area expected to contain the Palila. Note the sparse trees on fairly open grassland.

Here is a second shot taken as we climbed a little further up the Mauna Kea slope.

Found: A Family of Palila

According to the guide, on one recent trip they spent most of the allocated time hunting for the Palila and only found them as they were about to quit and move on. We got lucky and found one after about 15 minutes with another pair showing up shortly thereafter. In fact it appears that we had found a family unit with male, female and juvenile foraging together. The juvenile showed typical begging behaviour with fluttering wings and an adult was doing the foraging and feeding of the juvenile though regurgitation as described, for instance, in a Palila wikipedia article. This article says that both adults will regurgitate to feed the young in our case the male was feeding while the female stood guard, presumably looking for predators. If the wikipedia article is correct then perhaps they take turns feeding and guarding or perhaps the guarding behaviour only happens occasionally, for instance when a large number of two-legged, orange-vested homo sapiens are also foraging in the area.

If we only consider predators seen historically before the arrival of man on the islands the most likely candidates would probably have been the Hawaiian Short-eared Owl (Pueo) and the Hawaiian Hawk (ʻIo). It is not clear what threat we birders posed to the Palila though it was clearly not enough to drive them away. Whether or not the female would have stood guard where and when she did if we had not be there is unclear.

As mentioned earlier, introduced predators are currently one of the Palila’s biggest threats. These include feral cats and black rats (see for instance this article on the Palila from BirdLife International (birdlife.org). Mosquitos transmitting avian malaria have also proved very dangerous to the endemic populations of birds. They are also threatened by habitat degradation especially if it affects the growth and spreading of their primary food sources, the peas from the seed pods of the māmane plant and certain types of caterpillar. Introduced mammals such as sheep and pigs are particularly bad for disturbing the forest plants. Through hunting and fencing the threat of these has been reduced.

First Sighting: An adult male processing a māmane pod.

Our first sighting of a Palila was that of an adult male who was processing a māmane pod in the middle of a bush that provided the bird with some protection. The following 7 pictures, shown in the order that they were taken, cover a period of about 9 seconds. All of these pictures were cropped from the original size of 4000 x 3000 down to about 1200 x 800. The displayed images below are shown at a resolution of 640 x 400 though the full-sized cropped images can be viewed clicking on the image and following the link back to Flickr.

Video of the Male Foraging

The following is a short video that was taken starting 10 seconds after the last picture (above) was taken. You can hear the group leader describing the bird to some of the birders that were just then discovering it for the first time. Initially you can see the Palila alternating between working on the māmane pod and raising it’s head up to check its surroundings.

You can also hear the Palila in between the periods where it is working on the māmane pod and also after it appears to be done having released the māmane pod. Perhaps these calls were communications to the other family members that would be showing up in the seconds that followed the video. There may even have been a specific message to the juvenile that he (the adult male) was full and that it was time to eat. This might also explain why he dropped the pod. It’s not clear why they moved to a different location for the feeding. Perhaps it was because of our presence or perhaps because it is generally safer to keep moving.

Unfortunately there is a half minute gap between this series of pictures and the next series with adult feeding juvenile. The only thing that I recall from this period is that the juvenile and adult female arrived to join the adult male and then the female left again.

Second Sighting: A juvenile begging and being fed by the adult male.

The second set of 7 images were taken over a period of 13 seconds starting 63 seconds after the last picture in the first set or about 38 seconds after the end of the short video. As mentioned, in these 38 missing seconds the male moved to a different perch and a juvenile and an adult female flew in to join the adult male. Only the juvenile stayed to be fed by the adult male while the female flew off to, it appears, stand guard (see the third sighting section below).

The sequence between the adult male and the juvenile clearly shows the begging behaviour as well as the regurgitation and transfer of food from adult to juvenile.

The final image was taken 5 seconds after the previous one and shows the juvenile left alone and somewhat hidden in the foliage while the adult male had moved on, perhaps to start a new cycle of processing māmane pods prior to the next feeding cycle at which point he would call the juvenile to join him there.

Third Sighting: An adult female on guard duty.

The third set of 5 pictures were taken over a period of 24 seconds starting 18 seconds after the last image in the second set.

The adult female Palila, which made a brief appearance off camera took up a position 100 feet or so from where the other two birds were positioned. Her perch at the top of a bare branch gave her good visibility. She chose a bush that kept all of the birders, which had broken into several groups by this time, on one side of her, perhaps in order to be able to see all of them at once without continually having to look in opposite directions. As the photos show, she still does look away from time to time, perhaps scanning for other possible threats. As mentioned previously, the two historic threats where probably the Hawaiian Short-eared Owl (Pueo) and the Hawaiian Hawk (‘Io). At this point in our trip we had already seen 5 of these owls hunting (one near where we found the Palila) and we had one unconfirmed hawk sighting.

I was impressed by the fact that both adult Palilas were caring for what was clearly a juvenile bird. The splitting of the task of feeing the young was split into roles of foraging and standing guard. It would have been nice to know if they switched roles from time to time. Many species, particularly migratory ones, leave their young to fend for themselves at a much younger age or only one of the adults take responsibility for the young.

Final Thoughts

I acquired my Panasonic FZ-200 camera to help with bird identification but on several occasions it has proven useful in seeing behaviours that I would never have noticed using just binoculars. The ability to capture large numbers of pictures and even videos with sound provides the opportunity to analyze different aspects of bird sightings that happen too quickly in the field.

It would seem that my camera is rapidly replacing my binoculars as my primary birding equipment. Here are some things that I might change in the future that might lead to better results:

Take more pictures and make more use of burst mode. You can always delete them later.
Take more video clips. Images can be extracted from these videos though not with the same resolution. Video also records sound which can be useful in understanding bird behaviour.
Bring a tripod. A remote control cable might be useful as well for the still shots.
Make sure that the memory card is fast and has lots of space. Bringing extra fast cards will encourage taking lots of pictures and videos.
Add a directional microphone that plugs into the audio in jack on the camera.
Get more people involved. It would be interesting to see if better behaviour could be captured with a coordinated group of birders taking pictures and videos together. The camera clocks would obviously need to be either calibrated or synchronized to help determine the order of various events.

It was a fun way to get introduced to a new bird and, while it took a lot of time post-processing, it was definitely more satisfying than a brief sighting and a simple pencil mark on a checklist.

For More on the Palila Check Out the Following Links

The Palila article on Wikipedia.

The Palila Status at BirdLife International (birdlife.org).

The Mauna Kea Forest Restoration Project website from the Hawaiian state government has much more detailed and accurate information on current status and threats to the Palila.

The Facebook page for “A Paradise Lost”, an animated movie about the Palila directed by Laurie Sumiye.

Five Harlequin Ducks Video

Adventures in Cackling Goose Subspecies Identification

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Sardis Pond and a Whole Lot of Geese

I saw my very first Cackling Geese on Friday September 20 while on an outing with some of the members of a bird-photography course that I am taking. We were at our last stop of the day which was Sardis Pond which sits in the middle of Sardis Park in the middle of Chilliwack.

My one previous visit was in late May when the bird population consisted of small numbers of Canada Geese, Mallards, Red-winged Blackbirds and a few Wood Ducks. Later in the year, I was told, the pond would get more interesting as a lot more birds move in for the winter including thousands of Canada Geese and, in recent years, a small of population of Cackling Geese.

The photography instructor Ken, with his black-belt in camera skills, thought it worth making a quick stop to look for early cackler arrivals before calling it a day.

We weren’t disappointed. The first thing that we noticed was the large number of Canada Geese that had already moved in. We estimated that there were probably 800 to 1000 of them.

Canada Geese have taken over in Sardis Park. Can you spot the two Cackling Geese?

After a few minutes of searching, Ken found 2 cacklers hanging out together and, over the next half hour or so, we took a whole lot of pictures.

That might have been the end of the story that would have ended with a checklist indicating two Cackling Geese. However, Ken noted a partial white neck ring on one of the two geese and we weren’t sure if it was significant. When I got home I took a closer look at both and wondered if they might be from different sub-species. This led me on a path over several days that would introduce me to the many of the pitfalls associated with bird identification – in this case, the attempted identification of the specific sub-species of the two Cackling Geese.

The process of trying to identify the subspecies for the 2 geese was quite educational and I decided that it was worth describing in some detail along with some lessons learned drawn from some identification mistakes made along the way. During this process, I was quite glad to have taken a large number of pictures of the two cacklers (over 50) as well as a short minute long video.

Introducing the Cackling Geese

The following picture shows the 2 cacklers side-by-side. The bills on each bird look similar in size and shape and definitely have the expected stubby form of the Cackling Goose . The bird on the right appears slightly larger, has a squarer head and a partial white neck ring. While you cannot see it in the first image, the second image shows the larger cackler (now on the left) to have a noticeable throat stripe not present on the smaller goose.

Two cackling geese from behind. Note the throat-stripe on the left bird.

The third picture, below, shows the two birds head on providing a good look at the colour of the breast. Both geese show a fairly dark brown. The size difference is also less noticeable in this view.

My usual first stop for bird identification is The Sibley Guide to Birds. My hard copy only lists Canada Goose since the Cackling Goose was only split from the Canada Goose into its own species in 2004 (in the 45^th Supplement to the AOU Checklist of North American Birds to be precise). The online version of the Sibley Guide on my iPhone and iPad is updated regularly and does the 2 species though does not contain the level of detail that would eventually be necessary.

Another extremely useful guide that I consulted extensively was the online Sibley guide: Distinguishing Cackling and Canada Goose. Finally, I relied on expert help from the Fraser Valley Birding forum to make up for my own lack of field experience in the fine details and the pitfalls of separating subspecies..

According to the online Sibley guide, the Canada/Cackling Goose species are divided into 7 Canada Goose and 4 Cackling Goose subspecies. Assuming that we had a pair of cacklers, the two most likely subspecies for our two birds are given below with descriptive information taken from different sources:

B h minima: The ‘Cackling’ Cackling Goose and the smallest of the cacklers. It is described as having a round head, short bill and dark brown breast with a purplish tinge.
B h leucopareia: The ‘Aleutian’ Cackling Goose. It has a dark brown breast and is slightly larger and has a squarer head than B h minima. Usually has a white neck ring and usually has a black neck stripe. The bill is longer than that of B h minima as well.

My first thought was that the smaller goose was a B h minima while the second had characteristics suggestive of B h Leucopareia (neck stripe, partial collar, squarer head, larger size).

However, there were several issues with the larger bird being a B h Leucopareia. First, the breast colour of both birds was very similar having the purplish sheen described for B h minima. Second, the collar should probably have been a complete collar and not partial as seen. In any case, both collar and neck stripe can occur on other subspecies and cannot be reliably used for identification according to the online Sibley guide.

If you read the entire online Sibley guide you will find some suggestions as to how to find Cackling Geese in a crowd of Canada Geese. First, they suggest looking for birds that group together as a good way to identify birds from the same family group or population. These 2 geese that we were following were definitely sticking together. Since male geese are typically larger than females, this could explain the size difference. The difference in head shape is a little problematic as I do not know how important that trait is for a positive identification. Reference [3] suggests that head shape is not a critical trait and should not be a primary consideration in identification.

Sizing up the Bills

A good method of separating a Cackling Goose from a Canada Goose is to look at the bill size. This can also sometimes be used to separate subspecies in as well as is the case with B h minima and B h Leucopareia. The online Sibley guide has a table showing the range of bill length for the different Cackling and Canada Goose subspecies. In particular, there is no overlap between B h minima and B h leucopareia. Measuring the exact bill length is not practical however all we really need to compare is the relative bill size.

Consider the first picture of the 2 Cackling Geese walking single-file. Both geese have their heads pointing in the same direction and are roughly the same distance from the camera. The following image shows only the heads of the two geese rotated such that their bills have the same orientation. I marked the upper and lower edge of both bills with pink lines that have the same length and orientation on both birds. Their bills are effectively the same length which, according to Figure 2 in Sibley’s Guide is strong evidence that if the smaller goose is a B h minima then the larger bird should be as well.

The following image shows the re-oriented heads for the larger cackler and one of the large Canada Geese that were present at Sardis Pond and that I captured in a picture where their heads were pointed in the same direction and where both were roughly equidistant from the camera.

A pink line on the lower bill shows my estimate of the bill length for each with the length in units used by the program that I used to manipulate these head shots. The resulting Canada/Cackling bill length ratio is about 1.74. If I assume that the Canada Goose is of the western moffitti subspecies that is common in the west then, from Figure 2 in the Sibley Guide the expected ratio would be about 1.66.

The evidence suggests that both of these cacklers were of the minima subspecies.

Seeing a new bird is always satisfying. Being given a challenging puzzle to determine the subspecies was, in many ways, even more satisfying than the new life-list check-mark. I certainly learned a lot more about the pitfalls of bird identification. In fact, I’m still a little worried about that not-so-round head on the bigger cackler so maybe this story is not over yet.

One of the big lessons learned for me was that taking lots of pictures is a good thing, even after I had several good ones to document the new species.

So what to do for an encore? Well, I’m told that the Taverner subspecies will be showing up in a few months…

Thanks go to Ken for spotting the pair of cacklers, to Gord for correcting some of my identification missteps, and finally to Sibley for the excellent online guide.

References

[1] Sibley Guides: Distinguishing Cackling and Canada Goose.

[2] Stokes Birding Blog: Cackling Geese subspecies in the East.

[3] Monterey Birds: Canada Goose and Cackling Goose.

Bird Migration Movie: Crossing the Gulf of Mexico

Ruby-throated Hummingbird by Matt Tillett (Flickr: Ruby-throated Hummingbird) [CC-BY-2.0], via Wikimedia Commons

I found this hour long online movie about bird migration across the Gulf of Mexico a couple of days ago. It does a good job of documenting the amazing migration that many North American birds go through each Spring and Fall. Birds as small as the Ruby-throated Hummingbird fly non-stop from the Yucatan to the Gulf coast of the US on their way to their breeding grounds further North, a trip that can take most of a day and cover 600 or more miles. The fall sees a similar migration in the opposite direction back to the wintering grounds in Central and South America.

Link

Among my favourite birds to watch in flight are the swifts. They are powerful fliers that most people will only ever see on the wing since they cannot perch like the swallows that they superficially resemble (they are more closely related to hummingbirds). A friend of mine recently brought a story a from Discover Magazine (This Bird Can Fly for Six Months Without Landing Once) to my attention. Equipping the some Alpine Swifts with motion sensing equipment, a group of Swiss researchers were able to show that the birds, which breed in the mountains from southern Europe to the Himalayas, can stay aloft for months at a time during their overwinter migration in southern Africa.

Amazing!

Link

The September 2013 issue of the Canadian online journal Avian Conservation & Biology features a number of short research articles associated with Quantifying Human-related Mortality of Birds in Canada.

Individual articles deal with the contributions from specific industries and activities including:

Vehicle Collisions
House Cats
Marine Commercial Fisheries
Offshore Oil and Gas Production
Industrial Forestry
Collisions with Buildings
Mowing and Other Operations in Agriculture
Oil and Gas Exploration in the Western Basin
Collisions and Habitat Loss from Wind Turbines.

All of the articles can be freely viewed online or by downloading a PDF version.

So, which one of the above categories do you think is the biggest contributor towards bird mortality?

The final article, A Synthesis of Human-related Avian Mortality in Canada, puts all the different sources of bird mortality into context. Table 3 in this article shows bird mortality estimates separated by source and split into the categories of landbird, seabird, shorebird, waterbird and waterfowl.

And the biggest bird killer? It is, by a long shot, the house cat with an estimated 135 million birds (almost exclusively landbirds) of which 80 million are attributed to feral cats and the remaining 55 million to the domestic variety. Compare these numbers to the total of 186 million dead birds per year and we have house cats killing over 70% of all birds killed from human-related causes.

There’s a whole lot of interesting information in this issue. Well worth a read.

UK’s Blogging Red Kites

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Blogging Birds is the name of a web-site run by a group of researchers at the University of Aberdeen in Scotland in conjunction with members of the RSPB (Royal Society for the Protection of Birds). The site’s byline, The lives of red kites, told by computers, sums up what the site is all about.

The Red kite is a species of raptor that, according to the web site, was once widespread in the UK and, after having been almost extirpated (down to 10 breeding pairs in Wales in the 1940’s) is making something of a comeback.

What the researchers have done is to fit several birds with satellite transmitters that provide accurate positions for the birds several times per day. These can be plotted on a map which anyone can see online. So far, pretty cool, but there’s more!

In addition to the geo-tracking, the researchers have linked in information from other databases that tell them about the areas visited by the birds. They know if an area is urban or rural and, based on land use information, can guess at how a bird might be feeding itself. They also know when a kite is near its home turf or if it is exploring far outside its normal range. Finally, if their path crosses that of one of the other tracked kites, they have information about their possible interactions with others of their species.

The final piece that let’s them create blog postings on behalf of the kites is something called Natural Language Generation which synthesizes all the data with known kite behaviour and spits out the weekly computer generated postings that anyone can see. Looking at the web-site today I see that they have four blogs on tap for the kites: Wyvis, Moray, Millie and Ussie. There appear to be other tracked kites as well with one of them, Beauly, mentioned in Millie‘s latest post for the week of August 12 to 18.

It will be interesting to follow one or more of the kites over longer periods of time. Perhaps these blogs can help to reduce the animosity that once almost led to the Red Kite’s extirpation from the British Isles.

Notes

Of the three most common North American kites, the Red Kite is closest taxonomically to the Mississippi Kite of the south-eastern US sharing the same sub-family (Milvinae) but different genera. The White-tailed and Swallow-tailed Kites are both from a different sub-family (Elaninae). All of these kites are from the family Accipitridae of diurnal birds of prey.

The related species of Black Kite is sometimes seen in England, usually during migration. Both it and the Red Kite are from the same genus Milvus and have been known to hybridize.

Glorious Twelfth or a Hen Harrier’s Bad Day

Red Grouse – King of the Game Birds

Red Grouse (Lagopus lagopus scoticus) - geograph.org.uk - 446843

Red Grouse : Trish Steel [CC-BY-SA-2.0], via Wikimedia Commons

What gives the Red Grouse its royal title?

First, it is the only game bird that is endemic to the British Isles and can be found throughout Ireland, Scotland, Wales and Northern England with some territory extending into England’s southwest.

Second, a flushed Red Grouse bird can reach speeds of over 70 mph (I have seen 80 and even 90 mph used in different sources). The greater the speed, the greater the challenge to the hunter, particularly during the pinnacle of game hunting – the driven hunt.

In the driven game hunt, a row of 8 to 10 guns (the hunters) line up a certain distance apart, each in their own butt or stone box which provides some shelter, protection and concealment. The guns face in the direction from where a volley of Red Grouse, flushed by a line of beaters, will appear. The gun is now confronted by some number of birds, between a pigeon and a mallard in size (a typical weight is 600 g), coming at them usually low to the ground and fast enough to break the speed limit on any public road in Great Britain or Canada. The hunter’s task is to shoot as many of them as he can without injuring either beater or neighbouring gun. In principal, the hunt can continue in this manner all day long. Some historic hunts have seen enormous bags consisting of several thousand birds. There are reports of a single hunter shooting over 1000 birds in a single day. In today’s hunt, bags of 50 to 200 brace (1 brace = 2 birds) appear to be more typical for a line of 8 to 10 shooters during a day of driven hunting.

[A fascinating historic account of a driven hunt during the late Victorian Era can be found in the section on Grouse and Partridge Driving in the 1903 book Horses, Guns and Dogs.]

The hunters that come to the grouse moorlands for the challenge of shooting at these feathered-rockets make an important contribution to the economic activity of many communities where the appropriate conditions exist. The traditional grouse hunt that attracts the hunters has evolved a sophisticated management system that has the primary goal of maximizing the number of Red Grouse that are available for the shoot. There is much tradition and etiquette that comes with the today’s driven hunt, most of which are still run from private estates.

This year, the cost to participate in a driven hunt runs in the neighbourhood of £130 per brace with the expectation of a full day’s participation (I determined the cost from various sources including the Guns-on-Pegs web site which specializes in buying and selling shooting days). That works out to over C$100 per grouse. Because of the huge overhead required to hold a driven hunt (this article in the Journal of Applied Ecology gives a good accounting of this) they are very expensive to run and many estates are barely breaking even or losing money even in good years.

There is a second less expensive form of hunt referred to as the walked-up hunt in which a small group of hunters led by pointers, walk the heather shooting grouse as they are flushed by the dogs. Per brace, a walked-up hunt appears to cost roughly half that of a driven hunt.

Tradition and the Grouse Moorlands

Heather moorland near Tom Tallon's Crag - geograph.org.uk - 1508818

Heather moorland near Tom Tallon’s Crag (Andrew Curtis) / CC BY-SA 2.0
Much of the land here is managed as grouse moor as can be seen by the patchwork of areas on the far hillside where heather growth is regulated by controlled burning.

The Red Grouse does not lend itself to direct management through domestication as do other species such as partridge and pheasant. Instead, maintaining their populations is handled indirectly through the intensive management of the heather moorlands – also referred to as grouse moorlands or simply grouse moors. This lack of direct control means that the hunting season can vary in quality from year to year and location to location depending on weather conditions, predator populations, heather beetle infestations, and disease.

Managing the heather moorlands for grouse is very expensive and requires continuous attention. Gamekeepers will go to great lengths to ensure a large supply of healthy grouse, even walking the moors at night with a flashlight medicating any grouse that they find to help them fight or prevent disease. It should then come as no surprise that the same intensity is applied to managing the grouse’s predators. This usually means eradicating any predator that strays onto the grouse moors. The Red Fox may be hunted at night using lights and high-powered rifles or simply by using of snares. Widely acknowledged to be cruel and banned in most European countries, snares are also prone to catching and killing non-predators and protected species such as the badger (see for instance this 2004 article from Wales online).

Viewed from this side of the Atlantic, this ritualistic hunting supported by intense year-round management could seem odd, even barbaric. Long-standing traditions that are part of the fabric of a country’s cultural heritage can be very difficult to change. In some cases, however, change does occur. One example is the ending of the fox hunt in Scotland, England and Wales between 2004 and 2005.

Before passing judgement, consider some of the positive aspects of the grouse hunt as put forward by proponents of the hunt.

In Great Britain organizations such as the British Association for Shooting and Conservation, the Game and Wildlife Conservation Trust, and others seem to play a similar role for game hunting as Ducks Unlimited does in North American in support of duck and goose populations. In the case of the grouse, they help promote and maintain the heather moorlands for the benefit of the game birds and for any other bird or animal that may benefit as well. This includes, for instance, regular burning of patches of heather to keep larger shrubs in check and to encourage younger, tender growth that appeals to the grouse. One of the biggest benefits to the moors is from the reduced number of predators. Several threatened migratory birds breed in the moorlands and in those areas without these predators they thrive with breeding success reportedly 2 to 5 times that on unmanaged moorlands (as most pro-hunt organizations are quick to note).

The Game and Wildlife Conservation Trust has the following goal on their web site:

We promote our work to conservationists, including farmers and landowners and offer an on-site advisory service on all aspects of game and wildlife management, so that Britain’s countryside and its wildlife are enhanced for the public benefit

I suspect that the public benefit they refer to is a select part of the population that benefits from the hunt (the hunters, land-owners and surrounding communities). The benefit to the migratory birds is a convenient side-effect. Meanwhile, those other animals, the predators, that were removed or killed are not mentioned except in so much as they are part of the problem being managed.

The Plight of the Hen Harrier

Hen Harrier (from the Wikimedia Commons)

An key part of grouse management involves predator management. According to research used by some of the shooting proponents, the survival of grouse and other species can be several times greater when predators are kept under control. For the unprotected predators such as the red fox, carrion crow, stoat or weasel this is a death sentence should they be caught on or near grouse lands.

A number of raptors also fall on a gamekeeper’s list of predators however most of these are protected species making it illegal to kill them or disturb them while nesting. With tradition, jobs and large sums of money on the line it is not surprising that the battle lines are drawn between the gamekeepers and other hunting proponents and the ‘raptor lobby’.

[Some interesting insight into the ‘Raptor Lobby’ can be obtained from the Raptor Persecution Scotland blog.]

When discussing Red Grouse management and raptors, one species that is frequently mentioned is the Hen Harrier (Circus cyaneus; the Northern Harrier in North America). The moorlands are a terrain well suited to their hunting and nesting behaviour yet, despite the laws intended to protect them they are disappearing in many areas of Britain particularly those areas near grouse moorlands. They and several other raptors including Golden Eagles and Buzzards are frequently shot or poisoned.

This year in England is especially ominous for the Hen Harrier. An August 9th article by the Royal Society for the Protection of Birds (RSPB) entitled: Hen harrier on the brink of ‘extinction’ in England reports that this is the first year since the 1960’s that the Harrier has not successfully nested in England (they mean ‘extirpation’ not extinction of course). The Hen Harrier, once widespread in Britain, has been harassed by gamekeepers for centuries. It was previously extirpated around 1900 only to resettle mid-century. Despite the raptor protection laws, the return to England is proving to be short lived and its future status may be uncertain as long as the economic value of the grouse hunt remains high. Given the economic importance of the grouse hunt, it is hardly surprising that Harriers and other protected raptors are being persecuted.

On the side of the hunt, a 2009 article in the Journal of Applied Ecology, Hen harriers and red grouse: economic aspects of red grouse shooting and the implications for moorland conservation, presents ecological and economic arguments to justify keeping Harrier populations low. It provides good insight into the economics of the grouse hunting industry and the issues facing the Harrier and other grouse predators.

Other opposing research is not as quick to blame the Harrier and other predators but instead lays out a number of other reasons for long term and year-to-year declines in grouse populations including: conversion of heather moorlands to sheep pastures; deterioration in the heather quality that grouse rely on for survival; increased disease reducing survival rate; increased predation by foxes and crows attracted by increased sheep populations; afforestation; and so on.

In an effort to find real solutions, both sides of the debate have cooperated in some long term research projects to better understand the relationship between grouse populations and raptors such as the Hen Harrier. A Joint Raptor Study (JRS) was run from 1992 to 1997 to measure the scale of raptor predation on grouse and the effects that would be felt on the hunt. A new study called The Langholm Moor Demonstration Project started in 2008 and will last up to 10 years with the goal of finding solutions to solve the grouse-raptor issues.

I won’t go into all the details of these studies but one interesting thing that I did learn which shows some of the complexity of the problem, is that the Harrier’s main prey are voles and meadow pipits, not the grouse, and the availability of these influences where the Harriers decide to settle in the spring. It is only during the months that they are breeding that grouse chicks are at risk of being taken and diversionary feeding (providing carrion to the raptors) has shown the numbers of grouse chicks taken to drop by as much as 86%.

Watching the Magician’s Other Hand

One fact which nobody disputes is that grouse are good for the environment.

That’s a direct quote from an obviously pro-hunt 1996 article published in “The Independent” and accurately sums up the position taken by most pro-hunt organizations.

Having spent some time trying to understand the history, culture and economics surrounding the grouse hunt in Great Britain, I can’t help feeling like I am watching a magician doing an elaborate trick when trying to sort through the shooters’ arguments. While their main hand attempts to capture my attention with statements of environmental and economic goodness, there other hand is quietly doing whatever it takes to make sure the grouse are ready on August 12.

The arguments for and against the grouse hunt and predator management are many and, sitting on the other side of the Atlantic, I don’t feel qualified to mark the scorecard. Instead, I will direct my final thoughts in a different direction going back to what drew me to write this in the first place, the name given to the opening of the Red Grouse hunting season.

Introspection

They call it the Glorious Twelfth.

Being a long-time fan of Star Trek the word glorious makes me think of the Klingons, warriors with tradition and a code of honour, their battles gloriously fought against enemies that are, they hope, worthy adversaries. The grouse hunt certainly has its tradition, however I wonder if a Klingon would feel glorious standing in a box waiting for someone else find and deliver their quarry to them, killing wave after wave of them with no chance of the quarry fighting back, the biggest risk coming from a neighbouring hunter? I wonder if they would feel any honour participating in a sport for which so many foxes, crows, stoats, weasels, other predators and even innocent creatures that had been killed, sometimes cruelly, in order to ensure the maximum number of grouse for the final slaughter?

The Glorious Twelfth doesn’t really do the day justice. Perhaps, as suggested by the birder and blogger Alan Tilmouth from Northumberland, a better name would be Hen Harrier Day.

References and Other Interesting Links

Some of the interesting links that I found while researching this article are given below. Some were used directly for information while others are just interesting reading.

Glorious Twelfth

Wikipedia: The Glorious Twelfth
Shooting Times & Country Magazine (2011): The season’s final farewell
The Glorious Twelfth (Virginia: Firearms Training)

Hunting

Horses, Guns, And Dogs; 1903 by J. Otho Paget, George A. B. Dewar A. B. Portman, And A. Innes Shand; (See the section on Grouse And Partridge Driving.)
Wikipedia: Hunting in the United Kingdom
Wikipedia: Driven Grouse Shooting
Scotland regulations for moorland burning: Muirburn Code
Historic UK: Fox Hunting in Britain
Game Conservancy USA: Life is wild for our glorious grouse.
The Scottish Gamekeepers Association: THE WILDLIFE AND NATURAL ENVIRONMENT BILL – A SUMMARY OF CHANGES

Shooting Trip Providers

In the Press

Land Gazette (2009): Grouse mixed bag this season
Discotheque article: A commentary on the grouse hunt
theguardian.com: Letters: Nothing glorious about the twelfth
reuters.com (2011): Game over for grouse as UK shooting season begins
Wales online (2004): Snares ban demand after find at shoot

Visual Evidence of Mites

Identification

Of Mites and Nestlings

References

References

Mauna Kea and the Palila

The Palila Plan

Found: A Family of Palila

First Sighting: An adult male processing a māmane pod.

Video of the Male Foraging

Second Sighting: A juvenile begging and being fed by the adult male.

Third Sighting: An adult female on guard duty.

Final Thoughts

For More on the Palila Check Out the Following Links

Sardis Pond and a Whole Lot of Geese

Introducing the Cackling Geese

Sizing up the Bills

References

Notes

Red Grouse – King of the Game Birds

Tradition and the Grouse Moorlands

The Plight of the Hen Harrier

Watching the Magician’s Other Hand

Introspection

References and Other Interesting Links

Glorious Twelfth

Hunting

Shooting Trip Providers

In the Press

Game Conservation

Grouse, Hen Harriers and other Birds of Prey