Oriole Fledglings

Last Sunday, these two Baltimore Oriole (Icterus galbula) youngsters got their first view of the big, wide world. They were hatched in the pouch-like nest that their parents had built high in the outermost branches of a tree near the river. A dead branch allowed a pretty clear view of the high nest for we who are earthbound. One chick has moved out onto a branch, while a second is sitting at the edge of the nest. Orioles usually produce a clutch of 4 or 5 eggs, so another chick or two may still be in the nest, or perhaps have already set out.

Like most songbirds, oriole chicks have closed eyes and are hairless when they hatch. Such hatchlings are termed altricial. However, in one of nature’s many miracles, the chicks grow to close to the size of their parents and are fully feathered , ready to leave the nest and fly, in just 12 to 14 days! The parents will continue to feed the youngsters insects for a few days until they master flight and learn to find their own food. In the photo above, you can see the fledgling begging, whirring its wings and chirring to the parent, waiting to be fed.

Many songbirds raise two, or sometimes even 3 broods, or families, each summer and parents must work very hard to provide for their young. Sadly, many songbirds live short lives and die tragic deaths. These youngsters will have to contend with widespread habitat loss, pesticide poisoning, cats, windows, lights, towers, and other disasters-in-waiting ready to take their toll. These challenges are causing a slow but steady decline in songbird populations across the continent. In the last 3 to 4 decades, the songbird population has fallen by a horrifying 20 to 30%. How long will it be before, as Rachel Carson forecast, we face a silent spring? An excellent source of more information is Bridget Stutchbury’s book, Silence of the Songbirds, which I reviewed here. Some ways that you can help to protect songbirds are listed here:

How To Save A Songbird

Buy shade-grown coffee that is both organic and fairly-traded.

Buy organic produce

Avoid non-organic North American crops such as alfalfa, Brussel sprouts,blueberries, celery, corn, cotton, cranberries, potatoes and wheat.

Buy unbleached, recycled paper products

Turn off the lights at night in city buildings and homes during peak migration periods

Keep your cat indoors

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The Big Reveal

Once the trees drop their leaves, the nurseries that cradled the year’s bounty of baby birds are suddenly revealed. It’s amazing how well-concealed nests are during the summer. Of course, if you pay close attention to the actions of birds, and know where to look, it is possible to find their nests while they are active. However, I have been content to let the birds live their lives in my yard without my scrutinizing of their comings and goings to closely. Consequently, I have daily walked right past nests without knowing they were present until the fall.

Many American Robins (Turdus migratorius) build their nests close to our house in trees and hedges bordering the lawn and driveway. Robin nests are among the easiest nests to identify in the fall. Robins construct very sturdy nests, weaving grasses into a cup and plastering the walls with mud. They are the only builders of cup-shaped nest to employ mud in this fashion, so dried-mud is a pretty sure sign that you are looking at a robin’s nest. The nest pictured at the top of the post was built in a hawthorn tree. The nests above and below are further examples of robin architecture.

The robin who built the nest below included some twine in the construction.

This nest, located in a Amur Maple tree, features a strip of torn plastic. The mud isn’t conspicuous, but I got out the ladder and climbed up to take a closer look. Sure enough, the mud rim can readily be observed. For more on robin nests, see Robin’s Egg Blues.

Another readily-identifiable nest to be found in the bare tree branches is that of the Baltimore Oriole (Icterus galbula). Orioles weave a hanging basket that is typically secured at the rim or edges to a drooping branch. It is woven with various plant fibres and lined with fine grass, hair or plant down. The nests often hang in branches over roads, an adaptation, perhaps, of an instinct to build the nest over flowing water. The nests quickly become weather-worn once the trees lose their leaves.

Many nests are difficult to identify once their occupants have departed. Here is a nest with a scenic situation over water. It may have been built by an Eastern Kingbird (Tyrannus tyrannus). Kingbirds like to nest on a horizontal tree limb, about halfway between the tree trunk and its canopy. About 25 % of the time, the nest is located over water. Kingbirds build a bulky, untidy nest using weed stems, grass, plant down and rootlets.

The nest below is likely that of an American Goldfinch (Carduelis tristis). Goldfinches prefer to build their tightly-woven nest in a branch fork. Caterpillar webbing and spider silk is often used to bind the outer rim of the nest.

The builder of this large nest, over a foot across and high up in a larch tree, remains a mystery.

Not all the nest-builders were birds. This nest, possible belonging to Bald-faced Hornets (Dolichovespula maculata), has already started to disintegrate.

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International Migratory Bird Day

Baltimore Oriole (Icterus galbula)

With International Migratory Bird Day this weekend, the Globe and Mail featured an editorial about the decline of Boreal breeding birds today. The editorial is signed by Bridget Stutchbury, biology professor at York University and author of Silence of the Songbirds, Caroline Schultz, executive director of Ontario Nature, and Jeff Wells, director of science and policy for the Boreal Songbird Initiative. You can read the letter at TheGlobeandMail.com.

International Migratory Bird Day (IMBD), celebrated on the second Saturday in May, marks the height of the migratory season and celebrates the astounding journeys of millions of birds who travel thousands of miles from wintering grounds in the south to their northern breeding grounds. Their journeys are fraught with peril and many fall along the way. Every year, fewer migratory birds return. Now the Boreal forests so many breeding birds depend on are increasingly exploited and developed by industry. The populations of migratory birds are suffering one of the most precipitous declines of any animal group on earth. To raise awareness of the plight of migratory birds and celebrate their spring return, IMBD is celebrated in Canada, the United States and Mexico with bird walks and festivals. You can learn more about IMBD, including events near you at Nature Canada or Birdday.org.

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Robin’s Egg Blues

One of the nice things about the trees losing their leaves in the winter is the way that the activity of the bird community is revealed.
Nests hidden in the summer suddenly become conspicuous. There are quite a few nests to be seen in the trees around here, including the Baltimore Oriole’s nest (Icterus galbula) pictured above. There are also some nests in unexpected places, such as this nest I noticed in the hoophouse. Can you see it?

The hoophouse was once one of three that were used by a former owner as part of a nursery operation. The last owners of the property had 2 of the houses removed and allowed the third to deteriorate, its equipment unmaintained, and it was full of junk and garbage when we first viewed it. The wood for the garden monster is stored in here now. I noticed that high up on an old bit of machinery, there was a nest.

I climbed up to take a closer look at the nest. It was clearly that of an American Robin (Turdus migratorius), readily identifiable by the mud cementing the structure. Robins and swallows are the main employers of mud in nest construction, and the cup-like shape points to the former as the builder of this nest. When I reached my fingers over the edge of the nest, I could feel that there were still eggs in the nest. I removed it from its perch for closer inspection.

Obviously, something disrupted the robin parents after their eggs were laid. It could have been simply that someone closed the door to the hoophouse, cutting off their access. Four lovely eggs remain, sadly, never to hatch.

Normally, the female robin would incubate the eggs for 12 to 14 days. Like the young of most songbirds, robin hatchlings have closed eyes, are naked, and require feeding by their parents. Such hatchlings are termed altricial. These babies are very different from the hatchlings of birds like ducks and geese, who have open eyes and down when they hatch and are able to leave the nest within 24 hours of hatching. Those hatchlings are termed precocial.

The baby robins would have grown quickly. In just over 2 weeks, they would have been close to the size of their parents, would be fully-feathered, and ready to leave the nest and fly. The fledglings would continue to be fed and cared for by the male until they could manage on their own. Meanwhile, Mom would begin to incubate a second clutch of eggs. Robins raise 2 or 3 broods, or families, each summer.

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