Tag Archives: Bird Identification

Puzzler #7 (New and Improved): Rename that Hawk

Adventures in Cackling Goose Subspecies Identification

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.

Vancouver to Toronto by Train Day 3: Saskatchewan and Manitoba

Unity

We slept through most of Alberta waking early somewhere near the Saskatchewan border. The early light revealed a landscape of low hills, grassy fields, patches of mixed forests and wetlands hidden by early morning mist.

As the light increased it became clear that this was not the traditional flat Saskatchewan with its golden fields of wheat. We saw lots pasture lands with grazing cattle but little evidence of crops.

We travelled a half-hour through similar landscape before seeing our first small prairie town, Unity, just as the first sunlight poked over the horizon.

Unity is a town of about 2400 residents and sits near an intersection of the CN and CP rail lines. Despite its small size, the town is a thriving prairie community as demonstrated by the 2 large farm equipment dealers that we passed on the way in.

According to the town’s website, agriculture is their largest industry. In addition to the equipment dealers, the town has 2 inland grain terminals and an ethanol plant. Other industries include a salt mining plant and some oil and gas.

With an arena, 5-sheet curling rink, swimming pool and many other facilities Unity is a good example of how judging a prairie town by its census population can be deceiving.

Unity also lays claim to being the home to at least 2 NHL hockey players.

Geography

A short geography lesson will help to explain the terrain that we were travelling through.

Saskatchewan is 435 km wide across the north and 630 km across the south. There are few areas that were not scoured by ice during the last period of glaciation almost 20000 years ago. Our path would take us on a rough diagonal from south of Lloydminster on the Alberta border south-east to a point south of Yorkton near the Manitoba border. The total distance travelled in the province would be, by my estimate, about 700 km.

Since the retreat of the glaciers, a number of different ecological zones, or ecozones, have evolved and our path, it turns out, roughly follows the border between 2 of these. To the south were the Prairies, originally consisting predominantly of mid-grass and short-grass prairie but now almost totally transformed into agricultural land including those traditional Saskatchewan fields of wheat. To the north, the Boreal Plains, a land of rolling hilly terrain and mixed forests, with cold winters and short summers.

The transition between the two ecozones, and Saskatchewan’s northern agricultural belt, is a narrow ecoregion referred to as Aspen Parklands where grasslands and mixed forests compete for dominance in a landscape of rolling hills dotted with numerous bodies of water. Both Edmonton and Saskatoon lie entirely within this Aspen Parklands ecoregion while Winnipeg sits at its southeastern edge. This ecoregion is sometimes considered to be part of the Prairies ecozone.

Besides supporting agriculture the Aspen Parklands also supports a large diversity of wildlife, particularly during the summer months when numerous species of birds were present having migrated from their southern wintering grounds to breed. This is the landscape that we would travel through most of the day.

References:

Canadian Biodiversity: Ecozones,

Ecological Framework of Canada: Ecozones and Ecoregions of Canada

Aspen Parkland (Wikipedia),

Aspen Parkland (Ecological Framework of Canada)

Water

One final diversion to talk about water. The importance of water on the prairies should not be understated.

About one eighth of the province’s 650,000 square kilometers is covered by fresh water. The landscape that we saw from the train certainly supported this and we were definitely impressed by the number of ponds big and small. This may, however, have been a wetter year than most.

Direct precipitation on the prairies can be highly variable from year to year and multi-year periods of lower rainfall can occur naturally. There is some evidence that the 20-th century was unusually wet and that a much drier climate would be more typical of the current post glacial period.

Because of a rain-shadow caused by the Rocky Mountains, precipitation also tends to be higher as you move further east. The many ponds provide an important storage mechanism to help maintain a supply through dry periods. Additional water flow comes from snowmelt in the mountains which is carried through the prairies by several river systems.

So what’s the point to this discussion on water? It is my attempt to highlight the fragility of the prairie ecosystems and, more specifically (as a birder), the breeding grounds for many species of avian fauna. The ponds that many birds choose for nesting are typically quite shallow and many would not exist in periods of extended drought or even in a drier than normal year.

Many of our migrating bird species may appear to have healthy populations now but their long term survival may be far from certain should there be long term decreases in surface water availability for breeding each summer. In light of increased concerns over climate change, we should be concerned.

A Land full of Ponds full of Birds

I like to watch birds (you should have figured this out by now).

So, here we were, travelling through Saskatchewan along a path that would take us through prime breeding territory for many species of birds in the middle of their breeding season. Had I known what to expect prior to the trip then I would have been more prepared.

Since I had not done my homework, discovering the quantity of ponds and birds was a surprise and a revelation that, if nothing else, underlined the importance of these breeding grounds to the survival of many bird species.

Unlike those birds that were nesting in the forests or the grasslands and which would be virtually invisible to us, those nesting in and around the wetlands were often easily seen from the moving train.

Arriving at a positive species identification, on the other hand, was not so easy.

Bird Identification from a Moving Train

As we attempted to identify some of the birds that we were seeing, a few problems became evident. First, with pond after pond flying by, the experience was more like a rapid-fire, bell-ringer quiz than a quiet Sunday morning at your favourite wetlands or park.

Using binoculars proved to be a challenge even with image stabilization. Once you spot and select a target bird, you have, at most a few seconds to study that bird before it disappears out of sight and, at least for me, just locating and focussing on a bird can take more time than that. At higher speeds the lateral motion of the train can also be pretty severe making viewing even trickier.

Using a camera is a little different. Tracking is just as difficult but if you can use a rapid shutter speed and actually take a picture before a target is out of sight, you have a chance of getting a reasonable shot that, while it might not be photo-album quality, it may help with bird identification.

In the end, we found that the best results were obtained without binoculars or camera, instead relying on the ability of human vision to track and identify moving objects. The camera was still useful for documenting our trip and the binoculars would still come out during train stops.

For the record, some of the species that we were able to identify from the train included: Red-winged Blackbird, Yellow-headed Blackbird, Rock Pigeon, Franklin’s Gull, Black Tern, American White Pelican, Northern Harrier, American Magpie, Ruddy Duck, Mallard, American Coot, Brown Headed Cowbird, America Crow, Lesser Scaup (the Greater Scaup breeds further north), Mourning Dove and Northern Pintail.

A number of unknown ducks, diving birds and shorebirds were also seen. Someone better at identification than me would have identified more species.

Saskatoon

Our first stop of the day had been in Saskatoon around 09:00 AM. The camera battery was out of juice so we did not take any pictures but we were able to wander around and stretch our legs while some Chipping Sparrows and a small flock of Franklin’s Gulls provided some entertainment.

Saskatoon is the largest city in Saskatchewan with a population of about 220,000 (260,000 in the metropolitan area). It is a hub of many of the key industries in the province including potash mining, oil and agriculture. Unfortunately, the train station was at the south end of the city and we did not see much of the city proper.

Melville

Our second stop was in Melville at around 14:00. With a population of just under 5000, Melville is, as of the 2011 census, the smallest official city in Saskatchewan.

Melville is one of the standard CN stops and the train crew took advantage of it to change engineers. Our stop was relatively short but we were permitted to get off the train and walk around.

Arrival in Manitoba

After Melville, there were no more planned stops before Winnipeg though a couple of times we ended up sitting on a siding waiting for a freight train to pass. Shortly after Melville we arrived at the Qu’Appelle Valley.
The Qu’Appelle is a fairly large valley, gouged out by glacial melt-waters, that stretches from Lake Diefenbaker northwest of Regina all the way to the border with Manitoba. The small Qu-Appelle River runs through the valley. Shortly after we crossed into Manitoba, the Qu-Appelle ended, flowing into the larger Assiniboine.

We followed the Assiniboine for a while but in the end we parted ways to continue on a more direct route towards Portage la Prairie and Winnipeg while the river took a detour southward through Brandon.

Happy Birthday Rivers!

About 80 km into Manitoba, we passed through a town call Rivers. I only found out later that Rivers was celebrating its 100-th anniversary in 2013 with the last day of celebrations being July 7, the day we passed through.

Happy Birthday Rivers!

Unfortunately, we weren’t allowed to stop and help them celebrate.

Crossing the Assiniboine

Around 20:30 we finally crossed the Assiniboine River and pulled into the main train station in Winnipeg. Our 90 minute stop provided enough time to explore the area called the Forks sitting on the north side of the Assiniboine where it meets the Red River.

Hard to miss was a music concert going on with a large crowd of onlookers watching and occasionally dancing to the music. Exploring further, we found some interesting art and eventually came across the Oodena Celebration Circle, an amphitheater built to celebrate 6000 years of aboriginal peoples in the area.

Surrounding the central amphitheater were 8 Oodena Constellations designed around different constellations and stars and their associations with the seasons and the cultures of different native peoples.

On our way back to the train station, we passed by the Canadian Museum of Human Rights, a new national museum slated to open in 2014.

Winnipeg is the home to many, perhaps most of the train staff. When we left Winnipeg it was with a new crew that would see us all the way to Toronto.

It wasn’t long until the sun had completely set and we had arrived at the end of our third day.

Kevin's Nature Blog

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