Just for fun.
Find and identify the bird(s) in this picture. It was taken in my backyard a couple of days ago.
Just for fun.
Find and identify the bird(s) in this picture. It was taken in my backyard a couple of days ago.
It’s been pretty quiet on the birding front but I decided to go on the Nanaimo/Parksville Sunday bird walk to Bowen Park. In the heart of Nanaimo, this park is a jewel with most of its 36 hectares undeveloped.
The walk starts in the parking lot, near the first hole of Nanaimo’s Disk Golf course where we quickly spotted a Brown Creeper while waiting for the group to assemble. This one was quite vocal (for a Creeper) emitting a double note call at fairly regular intervals making us wonder if it was a young bird.
It was pretty quiet today. There were no Starlings or House Sparrows which helped keep the BQI (Bird Quality Index) high.
Shortly after we started down the birding trail we discovered a fairly large paper wasp nest. What I liked was the colour and pattern — different from the grey nests I am used to. Perhaps mocha is this year’s colour in paper-wasp real-estate.
A bit further, someone noticed an interesting spider web hanging between trees. With a bit of light that made it through the thick forest canopy it looked a bit like a suspended compact disk.
Next along the way was a Pacific-slope Flycatcher, making short foraging flights, returning to the same perch. He was quite cooperative, hanging out a few meters from the path so that everyone could get a good look or take a few pictures.
Pileated Woodpeckers frequently are oblivious to us birder-humans as we take shot after shot while they peck away at the trees. This female was pecking at various trees, occasionally do light renovations to existing holes. With the dark under-canopy, the camera shutter speed was in the 1/100 to 1/200 range so you had to snap your shot during the bird’s brief bouts of pounding or the image would be heavily blurred.
We saw a Barred Owl along the way but getting a good image would have been a challenge so I didn’t even try. The following two owls, however, cooperated with my picture taking:
Almost at the end of our outing, we found our ‘Bird of the Day’ — an American Dipper. It was hanging out in a shaded spot at the edge of the Millstone River. The BQI definitely jumped when we found this bird.
That was it. About three hours at Bowen Park. Total species count: 25.
This walk was organized by the Nanaimo Backyard Wildbird and Nature Store. They can be contacted for more information on future Sunday or Tuesday outings.
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.
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:
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:
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.
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.
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.
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.
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.
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.
I have listed below some of the interesting references that I found online.
 This 2005 reference contains some good high-level information on mites: Common Lice and Mites of Poultry: Identification and Treatment.
 One of the best short summaries on bird mites that I have found: UW Madison Department of Entomology information sheet.
 Good reference from Iowa State University: Bird-Mites.
 A good 2014 review article: Mites and birds: diversity, parasitism and coevolution.
July 21: As of yesterday the Pacific-slope Flycatcher nestlings are 10 days old. Their eyes are opening and feathers are starting to show. They also appear much more restless than in previous days and I’m a little worried that one might fall out of the nest. It’s more than 6 feet down to the concrete steps so a fall would, I imagine, be fatal.
The adult birds spend most of their time foraging and only at the nest for a few seconds every few minutes. So, I thought that I’d try to get a better between-visits picture of the nestlings with my Panasonic FZ-200 camera whose 24x optical zoom lets me fill the image whereas the Logitech 920 webcam, used for my videos, has no optical zoom so cropping is the only way to “zoom in” and that results in a lower resolution image. Here is the best picture that I was able to take:
I had just focussed on the nestlings, who were alone in the nest, when the adult male flycatcher appeared in the foreground. Because of the low-light I was using a large aperture with poor depth of focus which put the adult bird slightly out of focus. It’s a nice subtle effect.
The camera picture also highlights something else not so nice. If you look closely at the vinyl siding behind the nest you can see a number of small black specks. Reviewing the webcam videos shows that these specks are actually moving around. They are concentrated around the nest suggesting that they are some form of parasite associated with nest and birds. I reviewed previous days’ videos but July 21 was the first day that the specks were visible. My suspicion is that they are bird mites which Doctor Google tells me would not be a good thing. More research needed.
I was taking the 11:00 am ferry from Tsawwassen to Schwartz Bay when a loon near the boat decided to take flight. I captured a bit of it with my camera in burst mode with a shutter speed of 1/800. You can get a good sense of the cartoon “running on water” take-off. Perhaps I should call it a Looney Tunes take-off.
Back in August of this year, the 14th to be exact, I was walking along the waterfront in Sidney, BC when I caught a gull red-handed (or red-billed) trying to swallow a sea star. Here’s the sequence of 4 pictures that I took over a half-minute or so:
The gull does not seem to be having a lot of success.
Then, I was looking through some older images yesterday and found another sequence of 4 images taken in March 2016 at Neck Point Park in Nanaimo:
The first image shows the gull with the sea star in its mouth. The following three images show the gull swallowing the sea star. It had to extend its neck which, as you can see by the white spot on the rocks appearing in the third image, triggered a ‘movement’.
I sometimes wonder why I don’t get bored going to the same birding locations month after month, year after year. A big part of it is that, on any given day, there is a chance that they will see something different or rare or perhaps even totally new.
This past Sunday, while on an organized outing with a bunch of local birders to Buttertubs Marsh Bird Sanctuary in Nanaimo, I got my “something-new” fix. In this case is wasn’t a new species of bird — instead it was an inter-species interaction that I had never noticed before – that of an American Wigeon stealing food from an American Coot.
The first of the two species, the American Wigeon (Anas americana), is a duck that is part of the genus Anas sometimes referred to as dabbling ducks. These duck may feed on land or on the water where they can tip themselves upside down and gather underwater plants up to several inches below the surface.
The second of the two species, the American Coot (Fulica americana), is in the family Rallidae of rails and looks a little like a small black chicken. These birds may feed on land, by dabbling in shallow water or by diving for plants.
I captured a short video of the food stealing behaviour (kleptoparasitism) with my Panasonic DMC FZ-200 camera. I may have had too much fun and gotten a little carried away with the presentation. You be the judge:
At one point there were at least 3 or 4 Wigeon-Coot pairs doing similar food-stealing dances.
On another occasion I watched as a Wigeon tried to manage two Coots at the same time and seemed to spend a lot of time in the middle trying to decide which way to go. Not a good strategy for a low-intelligence bird it would seem.
Some further comments and other notes resulting from forays into online ‘research’:
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.
 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
 Juan A. Amat & Ramón C. Soriguer, Kleptoparasitism of Coots by Gadwalls, Ornis Scandinavica 15: 188-194. Copenhagen 1984.