Photo by Dan
Feeding birds in one’s yard makes for excellent photo opportunities. The birds come in close, and are distracted by the food, so you can sneak in and get some great up-close shots, providing you don’t mind having the feeders in the background. Sometimes, if you anticipate where the birds are going to land, you can get some good photos of them coming in and waiting their turns for the feeders, too. Between Dan and myself, I have quite a few pictures of birds at feeders. Many don’t make it up to the blog, for various reasons. A few do, however, particularly ones of new birds, or interesting behaviours or observations.
Photo by Dan
Today’s post falls into the latter, sort of. We had a cold snap roll in, and along with the four inches of snow it brought, the temperatures have dropped to about -10 oC (14 oF). It’s the sort of weather that drives birds to feeders in droves. We’ve had some 20+ Blue Jays visiting the platform feeders regularly, a dozen American Tree Sparrows, and the regular chickadees, nuthatches, and Hairy Woodpeckers. Also the above American Goldfinches. Back in the fall I bought a nyger sock for the finches, partially because it was cheap (it was $10, filled, while the traditional tubes were $12, empty), but also because the tube that we had, hand-me-downed from my mom, had accidentally gotten stepped on at some point in our settling-in process, and we needed something to replace it.
I’d never tried a sock feeder before, but had read positive things about them, one being that they can serve more birds than a tube can, since the tube has a limited number of openings to draw seed through, but a sock can be perched on from any angle and seed taken from anywhere. Right now all we have are goldfinches coming to the yard, but pretty much any finch interested in nyger seed may use the feeder, since finches in general are acrobats when it comes to eating, able to hang upside down from a branch (or nyger sock) to access seeds. Because of the way the feeder was hung next to a branch, though, we also spotted an American Tree Sparrow perched and reaching over to grab a few seeds from it. I didn’t get photos of him, which is too bad.
Masses of goldfinches aren’t especially unusual, as we can probably expect to see them at the feeders anytime we have a bit of inclement weather this winter, but these were the first real feeding frenzies of the season. I’m thinking I may go out and get a second sock, since even though more can cram on a sock than a tube, there were still more birds perched on the branches than there were on the feeder. Goldfinches are a squabbly bunch, a bit territorial once they’ve picked out a good feeding spot, reluctant to let another get too close in case they try to usurp it. You see that with Common Redpolls, too, the other finch that regularly comes around in large flocks. Pine Siskins are another species that favours nyger, but tend not to visit in quite the numbers that the other two do. We had siskins flying over the house in late fall but haven’t heard any lately. They were forecasted to leave the province for locales further south by the Ontario Field Ornithologists‘ resident Finch Forecaster, Ron Pittaway, so we may not get many, or any at all. Redpolls should show up, though, and Dan heard one in the yard today. It hasn’t made a visit to the feeder yet, however.
Goldfinches at this time of year are often mistaken for a different species of bird. Most people think of the bright gold-and-black male when they think goldfinch, but in the fall the males moult out all their bright feathers and adopt the drab plumage of the females for the winter. It’s better camouflage than the flashy colours, and while the yellow really attracts the attention of the girls, there’s no advantage to being bright at this time of year. You can still tell the males from the females if you look carefully. Males will often retain some of the brighter yellow around their face and throats, but failing that, they will have crisp black wings, while females will generally have brown-black wings. You can also tell age – adults have relatively white wingbars (sometimes tinged brown), while those of birds hatched this summer will be mostly brownish. Hatch-year males won’t show all that yellow around the face, only the adults will (it’s “left over” from their summer breeding plumage), which is another indicator of age/sex class. Of course, like with anything, there will always be intermediates that you may not be sure about. Most of the birds coming to our feeder today seemed to be adult males, though many were sort of intermediate. Only one I was definitively sure was a young bird, shown above.
Photo by Dan
Although we have goldfinches in our yards year-round, they are a migratory species. The birds we have at our feeders right now aren’t the ones that will be breeding here next summer, but short of banding studies where you can mark individuals, it’s difficult to tell the difference. They’re short-distance migrants, moving just far enough south for it to feel warm compared to where they came from. Being regular feeder-visitors, they are perhaps able to get by a bit further north than they would naturally go, since their foraging is supplemented by artificial food sources (the source is artificial, not the food). However, don’t worry about your food running out or removing your feeders if you’re gone for a while – birds are resourceful, and they’ll just move on to the next feeder or food source, or head on further south if there’s not enough where they are.
Dan commented this evening after taking Raven out to pee that he can’t help but keep envisioning some poor goldfinch sitting on a branch somewhere, shivering its tail feathers off, and he just doesn’t know how they do it. Staying warm in the winter is definitely a challenge. Right now the temperature outside is -17.5 oC (0.5 oF), and still dropping. Even bundled up to my max, with my long johns and down jacket and a couple sweaters and two pairs of socks, I would still freeze if I just sat still outside all night. So Dan’s question is a valid one – just how do the little birds do it?
They actually employ a few strategies to make it through cold winter nights. The first is in the form of adding extra insulation by fluffing up all their feathers. In doing so they trap air against their skin. Air is an excellent insulator, and is the premise behind the functionality of a down jacket – down works so well because it traps air in all the tiny little gaps between the fluffy feather barbs. Fluffing their feathers is a bird’s equivalent of throwing on an extra coat.
The second is an evolutionary adaptation. The arteries and veins that go down to their feet run side-by-side down the leg. The feet, exposed to the ambient temperatures as they are, can get quite cold. As the blood from the body flows through the artery down to the feet, the blood that’s in the feet runs back to the body in the vein right beside it. The heat in the arterial blood gets transferred to the heat in the venous blood, so that the venous blood is warm when it reenters the body, and the arterial blood is cold when it reaches the feet. Often, in very cold temperatures, the blood in the feet may be only just above freezing – just enough to keep the tissues in the feet from freezing and developing gangrene. There are no muscles in the feet, only tendons and bone (the muscles that control the toes are located up on the thigh and are protected by feathers), so keeping the feet warm isn’t as important, as long as they don’t freeze. By reducing the temperature of the blood servicing the feet the bird is able to avoid unwanted heat loss through their uninsulated skin.
And finally, they seek out sheltered spots, out of the wind and snow, to spend the night. This could be tucked up in the protection of some evergreen branches, or against a trunk, or in a shrub beside a snowbank. Some birds might use tree cavities or bird boxes. By minimizing their exposure to wind and other weather they can reduce the amount of heat lost. As well, birds that huddle up against a tree trunk or other solid object can benefit from the small amount of infrared radiation (heat) the tree or object builds up during the day and then releases overnight (you’ll sometimes see rings of melted snow around the base of a tree trunk, which are caused by this infrared radiation). They stuff themselves with seeds during the day so that they have a huge store of energy available for overnight. They spend the night shivering, which can burn off as much as 7 to 15% of their body weight – so it’s imperative that they put on that equivalent during their foraging during the day. This is like a 150 lb person burning off 15 lbs overnight while they sleep – and so having to pack on 15 lbs of fat during the day to accommodate for it (otherwise you’d get real thin real quick). Although we think of shivering as a bad thing, it is an animal’s normal way of generating extra heat in cold conditions, since they can’t just curl up by the fire or pull up another duvet. Birds really are amazing critters, surviving in conditions we would consider unimaginable.
The birdfeeders are hung just outside the windows where we can see them easily from indoors. The cats like to sit on the windowsill and watch, as well. The buzzing activity at the nyger feeder caught Merlin’s attention, and he sat and watched them for a while as they darted in and out, squabbling and scattering and coming back again. We don’t let them out to wander, so this will probably be as close as Merlin will ever get to a bird (at least, I hope so), but he seemed content to just birdwatch.