Tuesday, May 24, 2011

losing our common farmland birds: the Barn Swallow

this photo of the Barn Swallow courtesy of Creative Commons

A bird that has pooped on every rural doorstep from Nova Scotia to Vancouver Island is now a threatened species in Canada. Earlier this month, COSEWIC (Committee on the Status of Endangered Wildlife in Canada) met in Charlottetown, PEI to assess the conservation status of 40 Canadian wildlife species. Up for discussion amongst several fishes, molluscs, insects, whales and amphibians, was a bird that every Canadian farmer knows, the Barn Swallow. Why designate a species that still seems very common? The short answer is because its numbers have fallen by as much as 76% in the past 40 years. If that continues the bird that gives the meaning to "swallowtail" will be all but gone by mid-century.

In my mind, this designation of one of the continent's most numerous and widespread birds is a sign that we have left the initial phase of bird decline and entered a new era. In general (there are exceptions) most of the species on COSEWICs list have had rather narrow niches and restricted breeding ranges making them particularly vulnerable. It's one thing to list a long-billed murrelet or a sage thrasher, because we don't have a lot of old growth Douglas Fir or Silver Sage habitat left. But we know we have reached another level of ecological dysfunction when we start listing the adaptive birds that have become habituated to our disturbed agricultural landscapes.

Here is the "Reason for Designation" from COSEWIC's database:

This is one of the world’s most widespread and common landbird species. However, like many other species of birds that specialize on a diet of flying insects, this species has experienced very large declines that began somewhat inexplicably in the mid to late 1980s in Canada. Its Canadian distribution and abundance may still be greater than prior to European settlement, owing to the species’ ability to adapt to nesting in a variety of artificial structures (barns, bridges, etc.) and to exploit foraging opportunities in open, human-modified, rural landscapes. While there have been losses in the amount of some important types of artificial nest sites (e.g., open barns) and in the amount of foraging habitat in open agricultural areas in some parts of Canada, the causes of the recent population decline are not well understood. The magnitude and geographic extent of the decline are cause for conservation concern.

There are undoubtedly many things behind the decline of this and other aerial insectivores (the Common Nighthawk, the other swallows and swifts, and many flycatchers), but the common denominator here is the food they eat: flying insects. The one insect we pay attention to, the European Honeybee, has experienced alarming declines in many areas of the continent in recent years. No one does Breeding Insect Surveys the way we have been doing Breeding Bird Surveys for more than forty years, so we have no baseline from which to measure the populations of our bugs. It seems a fair guess, given our ongoing toxification of soils, air, and waterways, that the chemical compounds we make and release into the environment--many of them specifically designed to kill insects--are affecting the breeding cycles and abundance of the creatures our insectivorous birds depend on.

Bird Studies Canada's Director of National Programs, Jon McCracken, wrote about this three years ago in a BSC newsletter. Jon does a fine job of presenting the alarming data and then discussing the whole range of possible factors contributing to the decline of our aerial insectivors. Not a happy read but it helps you understand why a bird like the Barn Swallow is now on COSEWIC's roster.

I had a very brief chance to talk to Jon when I was visiting Ontario two weeks ago, at a talk I gave in Simcoe for the Norfolk Field Naturalists. I was delighted to meet Jon and the other BSC folks who made the drive from Port Rowan to come out for the event. If there is any hope in these dark days for our birds and biodiversity it is in the people working for NGOs like Bird Studies and others across Canada. They are doing all they can to protect the birds and the integrity of their habitats and to educate the rest of us. We have to do our part and heed the warnings that the Barn Swallow and other common birds send our way.

Eastern Kingbird on a pasture near Cherry Lake--another common aerial insectivore in Canadian farmland that is declining each year.

Thursday, May 19, 2011

Book review and some bird photos from trip to Pelee Island

Pelee Island, Ontario. SpringSong Bird Festival.
While chasing a trio of blackburnian warblers one early morning last week I came face to face with this winsome creature beneath the Carolinian canopy of hackberry, oak, and shagbark hickory trees. We clapped eyes and stared at one another for a solid minute, sixty feet separating us. I may never see a grey fox again in this life, for it is one of Canada’s rarest mammals, but in that minute I sensed a kindred intelligence and awareness behind those eyes.

You may see the same thing when you look into the eyes of your beagle or palomino, but what exactly else is happening, and how much can we attribute to the lives and minds of the other animals we are crowding from this earth?

This is the subject of a fine new book by Dale Peterson, author of the acclaimed Jane Goodall: The Woman Who Redefined Man. The Moral Lives of Animals takes some steps toward redefining animal nature, but I found myself selfishly interested in what the book says about human nature too and where these “natures” overlap. Early on, Peterson gives us an historic perspective on how we in the West have regarded other animals and their capacity for moral behaviour. Contrasting Medieval conceptions of animals as intelligent but under-endowed beings who can be held responsible for their actions with the Cartesian view in which animals are seen to be machine-like, mindless beings, Peterson posits a third way, an understanding that while we share some intellectual and moral qualities with animals, they are different, not only from us but from one another. A whale mind is not like a cat mind.

Quoting Herman Melville’s Moby Dick as a springboard for his ideas on animal life, Peterson interprets for us the research of primatologists and other animal scientists, illuminating the lives and minds of elephants, bonobos, chimpanzees, gibbons, chickadees, hyenas, lions, lizards, frogs, wolves and many other creatures. Never technical or data-heavy, the narrative leads out into the jungle then circles back to human cultures and behaviour before making another foray into the wild. Without being shrill or sentimental, Peterson shows us again and again that we are sharing this earth with many other wondrous beings who in their own ways think, love, hate, console, avenge, grieve, and feel.

Which brings me back to my encounter with the grey fox on Pelee Island. As we looked at one another I thought I sensed something more than curiosity or fear in her. The way she moved, came to attention, and stared made me wonder what she was thinking about. A few days later I found out. Staff at the Pelee Island Bird Observatory, which hosted the SpringSong Festival, discovered her den with seven kits, about 150 feet from where I took the photo. Here is another shot of her.

Here are a few of the bird photos I took on Pelee Island during my stay as the guest birder at the SpringSong Bird Festival.

Black-throated Green Warblers were fairly common on the island

I saw more Nashville Warblers on the island than I have seen in 25 years of birding. Almost as common as yellow-rumped warblers are here.

Best looks at Blackburnian Warblers I have ever had. Must've seen ten or more in four days.

We get Black and White warblers at Cherry Lake, but they are hard to photograph

The star bird everyone wanted to see were the two male Prothonotary warblers hanging around the swamps at the south end of Pelee Island. There are only a few pairs now breeding in Canada so it was a treat to see them. Here is one last shot of a Prothonotary, dwarfed by the big tree behind it.

Share this post

Get widget