Winter finch arrivals

Each winter brings a new mix of birds to the feeders outside our windows. A flock of 100+ Common Redpolls, accompanied by Pine Siskins and Common Goldfinches, ate nearly 50 kg of niger seed during the winter of 2005-2006. Last year, we didn't see a single Common Redpoll or Evening Grosbeak. This year is another story altogether.

Evening Grosbeaks first appeared in September and have stayed. Presently, we have two or three flocks totaling about 50 birds.
Common Redpolls now festoon the niger silo and the snow beneath. A few of the paler Redpolls may indeed be Hoary Redpolls but there seem to be intermediately coloured birds as well. Some day soon I will step up to meet Jean Iron's Redpoll Challenge, which involves learning to recognize the four redpoll subspecies presently wintering in Ontario.

This year-to-year variation makes backyard birding all the more interesting. To some, these movements may seem erratic but they're not. The so-called "irruptions" of northern bird species are caused by failures of staple food crops in the boreal forest and beyond. Ron Pittaway has acquired some expertise in predicting the movements of "northern birds". His 2007-2008 Winter Finch Forecast is spot-on.

Cerulean Warblers in cottage country

Courtesy of Lana Hays
We were delighted to find at least two Cerulean Warblers (Dendroica cerulea) singing in the hardwood forest less than a kilometre from our back door. I recorded some sounds from the first bird we found singing on May 21, 2007. On May 23, we found two males countersinging 300 m from where we made our May 21 observation. The video begins and ends with a Cerulean song. There's some Red-eyed Vireo (Vireo olivaceus) chatter in between.

This follows our observation of a single Cerulean Warbler in the same woodlot in May last year. We don't know whether they're actually breeding but the habitat - mature, mesic upland hardwood forest - corresponds to that utilized by well-studied breeding populations at the Queen's University Biological Station, 200 km to the east. We'll monitor the site over the next few weeks for signs of breeding.

The Cerulean Warbler is a species of special concern* in Canada, where the population is estimated to be only 500-1000 breeding pairs. Some populations in the United States have experienced precipitous declines. One of the threats to the Cerulean Warbler is the destruction of the tropical forests in which it, and a suite of other Neotropical migrant songbirds, spend the winter. This is one of the reasons we choose to buy shade grown coffee [on-line] from Birds and Beans in Toronto.

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Update - June 3, 2007. This species isn't unknown from the Kawartha Lakes. In the late 1990's, Cerulean Warblers were found breeding near Buckhorn, about 20 km east of us. As far as we know, they haven't been found there in recent years. We visited the area two days ago and located two singing Ceruleans as we drove slowly and listened through the open window of our vehicle, during the middle of the day. No doubt, there are more in the area.

The forests are similar to those near our home - second growth with a canopy largely enclosed by even-aged sugar maple. Just over a century ago, these lands were cleared for farmland; however, the soils are thin along the edge of the Canadian Shield and much of the land proved not to be arable. Succeeding generations from the pioneering families abandoned these farm fields allowing the forests to regenerate. Cerulean Warbler populations along the southern edge of the Shield appear to be benefiting, faring much better than those in the core of their range in the United States.

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* Special Concern - A species of special concern because of characteristics that make it particularly sensitive to human activities or natural events.

COSEWIC. 2003. COSEWIC assessment and update status report on the Cerulean Warbler Dendroica cerulea in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. vii + 25 pp. Available here.

Hamel, P. B. 2000. Cerulean Warbler (Dendroica cerulea). In The Birds of North America, No. 511 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.

Orchids in our woods

This orchid, the Yellow Lady's Slipper, is widely distributed in North America, but it is not at all common in our area. While walking off-trail trough our woods today, we found a patch of Cypripedium parviflorum in flower. Many of the plants were damaged, evidently browsed by deer. We took a GPS waypoint of the spot and will check it out in coming seasons.

Here's the etymology of the generic name from the Home Page of California Plant Names: Cypripedium: from the Greek Kypris, a name for Aphrodite, and pedilon, "a slipper," alluding to the shape of the flowers (ref. genus Cypripedium).

On the march, in early April

While the vernal pools in which they breed are still frozen, the Blue-spotted Salamanders (Ambystoma laterale) are on the move.

Pitch perfect at the Mountsberg Raptor Centre

Chomper the Great Horned Owl with his interpreter.
Martha and I are avid consumers of so-called popular science. In the past year we've attended a whale watching excursion, Body Worlds 2, demonstrations of bird banding at two bird observatories, a guided tour of a Northern Elephant Seal reserve, and several natural history museums and aquaria. We've learned a little science and, with one eye trained on our fellow audience members, a little about communicating science.

The practice of nature interpretation is fast-changing. These days, there's a shrinking demand, and no value, in showcasing wild animals as being tamed and trained, or as one dimensionally cute or dangerous. In the last few decades humans have been able to formulate, and sometimes answer, some very good questions about the lives of animals. We have certainly come to better understand the ongoing threats to wild animal populations and their habitats. At their very best, interpreters can challenge and enrich our view of the natural world. This is exactly what we experienced recently during a 30 minute "raptor demonstration" at the Mountsberg Conservation Area, east of Toronto.

Mountsberg is run by Conservation Halton. The Raptor Education Centre is home to eagles, owls, hawks and vultures who, for the most part, have come out on the losing end of encounters with humans. None of the birds are releasable. The Centre offers a range of educational programs to school groups and other visitors.

During our visit we were introduced by Jenn, one of the staff, to several members of the raptor guild including the Turkey Vulture (Cathartes aura), American Kestrel (Falco sparverius), Barn Owl (Tyto alba), Eastern Screech-Owl (Megascops asio), and Great Horned Owl (Bubo virginianus).

Our interpreter held our attention throughout the demonstration as she detailed the amazing morphological and sensory adaptations of these creatures. The birds were very co-operative - the Barn Owls swallowed whole dead mice as if on cue, the Turkey Vultures divined the location of hidden meaty morsels in the grass and the kestrel spread her tapered wings. Jenn explained that some of these birds are crepuscular, that is, most active at dawn and dusk. She conveyed a good command of what is and isn't known about these species, avoided all jargon and infused her delivery with enthusiasm.

The presentation was excellent but then again, what a supporting cast! To some extent, the piercing gazes and long, curved talons spoke for themselves. What 11 year old child wouldn't be enthralled by the presence of a very composed Great Horned Owl perched on a gloved hand? But this wasn't a one dimensional presentation of raptors as consummate, awe-inspiring apex predators. Our understanding of these birds, and the place in the world we share with them, was transformed by Jenn's accounts of how each bird came to Mountsberg. Some were crippled through collisions with cars or stationary structures. Others suffered from deliberate and illegal human actions. Many of the resulting injuries were evident - a Turkey Vulture had a drooping wing, an Eastern Screech Owl had a permanent stoop and an American Kestrel had an opaque eye.

"Some of our birds have their injuries on the inside..."

Thus Jenn began her explanation of the phenomenon and consequences of behavioural imprinting, by which young birds removed from the nest never learn to recognise their own kind. Her frame was not the familiar Disney-like portrayal of the kooky "bird that thinks it's a human being!!!" but rather one of a psychologically damaged wild creature that cannot survive beyond a caged enclosure. The overall effect of learning the provenance of these broken birds was to help us understand that raptors aren't particularly good at problem solving and coping with most human-caused changes to their environment. Moreover, while these predators have an impressive suite of adaptations, they require all of them intact simply to meet the challenges of life in the wild.

Raptors, and owls in particular, carry with them an enduring mythology that is at best inaccurate, anthropomorphic and just plain silly. The staff and supporters of the Mountsberg Raptor Education Centre have done a remarkable job of helping to dispel these myths. Their alternative interpretation of birds of prey is holistic, science-based and inspiring. Well done and thank you.

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Photos: Great Horned Owl, American Kestrel and Eastern Screech Owls, by Michael.

More urban waterfowl, Barrow's Goldeneye

We made a little visit to northern California over the holidays. This pair of Barrow's Goldeneye (Bucephala islandica) was one of many unanticipated species we stumbled across on an afternoon when Christmas shopping was on the agenda. This attractive pair was in the company of many Common Goldeneye (Bucephala clangula) and Surf Scoter (Melanitta perspicillata), all swimming in the man-made Shoreline Lake at Shoreline Park in Mountain View. Whereas San Francisco Bay attracts millions of wintering water birds (USFWS, 1987), Eadie et al., note that no more than 100 Barrow's Goldeneye are thought to winter in the Bay area, which marks the southernmost limit of the winter range of Barrow's Goldeneye.
A trio of Northern Shoveler
We walked over to the levee flanking the managed sloughs and salt marshes of the Bay and were delighted to view thousands of ducks, geese, American White Pelican and shorebirds at close range.

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Photo Credits:All photos by Michael.
Citations:
Eadie, J. M., J.-P. L. Savard, and M. L. Mallory. 2000. Barrow’s Goldeneye (Bucephala islandica).(In) The Birds of North America, No. 548 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.
U.S. Fish and Wildlife Service. 1987. Birds of San Francisco Bay and San Pablo
Bay National Wildlife Refuges. U.S. Fish and Wildlife Refuge. Unpaginated.
Jamestown, ND: Northern Prairie Wildlife Research Center Online.
http://www.npwrc.usgs.govsfbay.htm (Version 22MAY98).

Urban Long-tailed Ducks, in depth

A highlight of last weekend was the several hours we spent observing waterfowl in Toronto Harbour. Gadwalls (Anas strepera) , Mute Swans (Cygnus olor) and Red-breasted Mergansers (Mergus serrator) were among the common waterfowl we seldom observe at our inland home, about 200 km to the north. Most impressive were the rafts of Long-tailed Ducks (Clangula hyemalis) visible, and audible, throughout our visit. Some aspects of this bird's life history and charismatic presence in Toronto merit comment.
www.gregnewby.com.
Long-tailed ducks nest as far north as the 80th parallel - the highest of the high arctic, farther north than any other waterfowl (Robertson and Savard, 2002). Many winter on the Great Lakes with a significant number in the Toronto area. While these birds are quite at home in the rough, open waters of Lake Ontario, they appear to make a very good living in the inner and outer harbours created by the Eastern Headland (Tommy Thompson Park) and Toronto Island. A summary of Christmas Bird Count data for the past 25 years reveals just how hospitable the waterfront is to these visitors from the north. Three years ago, a record high of 13,938 Long-tailed Ducks was recorded. Low counts in the 1980's and 1990's likely resulted from the freezing of near shore waters in the city. In more mild recent winters, ice has not formed on Lake Ontario.

The call of the male has been variously transcribed as ahr-ahr-ahroulit, ahang-ahóo, ow owooolee, ow ow owoolik, or unk-on-alik, take your pick. Whereas other ducks may vocalize solely during courtship or during aggressive encounters, the yodelling notes of Long-tailed Ducks seem to accompany all aspects of their highly social lives.

Click here to hear a chorus of Long-tailed Ducks (.wav file), recorded in Toronto, courtesy of the Canadian Wildlife Service.

Whether flying our feeding, courting or resting, Long-tailed Ducks vocalize continually:the song is always in season. Surely these must be among the most garrulous of animals. Beyond its volume and ubiquity, the call has always struck me as exultant - a ringing lyric with overtones as ancient as the tundra.

No less remarkable than the male's vocal repertoire is its very elegant, stream-lined appearance. George Miksch Sutton and his colleague Olin Sewall Pettingill Jr., spent the summer of 1958 documenting the breeding birds of Iceland. Long-tailed Ducks, then known in North America as Oldquaws, were common on the tundra. Sutton's comments on Long-tailed Ducks echo some of the wonder we experienced as we watched these birds foraging along the Lake Ontario shoreline.

Sewall had a wonderful experience photographing the diving Oldsquaw. Perched with his camera on the cliff edge not far from Gudrún Pálsdóttir's house, he had been able to follow the bird as it moved gracefully about, had fed on the bottom, and finally come up with big eyes sparkling and water running down its sleek plumage. I had watched many diving Oldsquaw in the American Arctic and knew how beautiful they could be.Iceland Summer (p. 93).

While Martha and I strolled along the boardwalk just west of Wards Island, we lingered to observe about 50 very animated Long-tailed Ducks that were calling and diving only a few dozen metres offshore. They dove more-or-less synchronously, each leaving the surface with a clearly audible "plop". From our slightly elevated position, we could track each bird by the bubble trail reaching the surface. After about a minute below, the birds would bob topside, many calling or chortling with apparent enthusiasm. After only a few breaths, the birds commenced their next dive.

Long-tailed Ducks swimming toward shore at Ward's Island

Long-tailed Ducks are perhaps the deepest divers of their clan. On the Great Lakes, commercial fishermen have recovered tens of thousands of drowned Long-tailed Ducks from even their deepest gill net sets, some 70 metres below the surface - a vertical descent equivalent to the height of a 23 story office building. Associated with this hyperbaric extreme, Long-tailed ducks have the greatest heart muscle mass, gram-for-gram, of any duck, goose or swan (Bethke and Thomas, 1988).

On its wintering grounds, the species is known to exploit a range of animal prey, including epibenthic crustaceans, snails and, in soft substrates, oligochaete worms. We could only speculate on the nature of today's meal. Given the shallow break of the shore and the close proximity of the birds we observed, we supposed they couldn't have been feeding at more than a few metres depth. Offshore an additional 20 metres, a pair of Surf Scoters also dove. Each would surface with a single cluster of dreissenid mussels held in the fully gaped bill. The scoter would then break up the cluster and swallow, apparently with some effort, a smaller clump of mussels.

In contrast, the Long-tailed Ducks, diving in shallower water, surfaced with nothing in their bills, suggesting that they were eating smaller, more easily manipulated prey. One possibility, given the time of year and the characteristics of the site, is that they were eating the freshly spawned eggs of Lake Herring (Coregonus artedi). While fish eggs have not yet been documented in the diet of wintering populations of Long-tailed Ducks in North America, a recent study in the Baltic Sea, off Lithuania, found that this species opportunistically exploited the "energy-rich" eggs of Baltic Herring (Clupea harengus membras) during the April spawn (Zydelis and Ruskyte, 2005).

Whillans (1979) noted that between 1880 and 1893, large numbers of gravid Lake Herring were harvested along the shore of Toronto Island. The stock disappeared over a century ago and to my knowledge, has not recovered. The return of spawning Lake Herring to these shores would certainly be noteworthy.

These highly energetic flocks of Long-tailed Ducks provide a glimpse of something truly wild - a very scarce commodity in such a built up metropolis. Against a backdrop that includes the CN Tower and completely industrialized portlands, it is deeply satisfying to note that the wild, exuberant presence of these birds is in no way diminished.

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Image Credits:
Photo Credits: Photo of male Long-tailed Duck (top) used with permission from Greg Newby Photography.
Christmas Bird Count graphic by Michael. Other Long-tailed Duck photos by Martha.
Citations:
Bethke, R.W. and V. G. Thomas. 1988. Differences in flight and heart mass among geese, dabbling ducks, and diving ducks relative to habitat use. Canadian Journal of Zoology. 66: 2024–2028.
National Audubon Society (2006). The Christmas Bird Count Historical Results [Online]. Available at http://www.audubon.org/bird/cbc.
Robertson, G. J., and J.-P. L. Savard. 2002. Long-tailed Duck (Clangula hyemalis). In The Birds of North America, No. 651 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.
Sutton, G.M. 1974. Iceland Summer. University of Oklahoma Press, Norman.
Whillans, T.H. 1979, Historic transformation of fish and communities in three Great Lakes Bays. Journal of Great Lakes Research 5(2):195-215.
Zydelis, R. and D. Ruskyte. 2005. Winter foraging of Long-Tailed Ducks (Clangula hyemalis) exploiting different benthic communities in the Baltic Sea. Wilson Bulletin 117(2):133-141.