August 25, 2019
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When it comes to raising baby birds, mothers have a whole range of strategies

Bob Duchesne | BDN
Bob Duchesne | BDN
Newly hatched great horned owl chicks are sightless, featherless, and helpless, and it takes another seven weeks to raise them to the point where they can leave the nest.

This was the buggiest year since the invention of bugs. Maybe that’s why so many baby birds have flooded my yard. I guess the birds and I view the world differently. Bugs see me as the feast. Birds see bugs as the feast. At any rate, my yard produced bumper crops of bugs and baby birds this year. So did yours.

We humans are accustomed to a single pattern of child-rearing. Kids stay with their parents until they leave for college or work, around age 18. Some even live in their parent’s basement until they’ve paid off their student loans, at the age of 50 or 60.

Birds have a whole range of child-rearing strategies, but it all comes down to two words that you don’t need to remember: precocial and altricial. Some babies are ready to leave the nest soon after they hatch. These precocial chicks are able to see, walk and even forage for themselves. On the other hand, altricial babies are still underdeveloped when they leave the egg. They are blind, immobile, featherless and in need of constant care.

[Read more Good Birding here]

Here’s where Mother Nature gets clever. As a bird, you are what you eat … and what eats you. Take, for example, ruffed grouse. Everything eats them. Even we eat them. A hen sitting quietly on her ground nest is well concealed and relatively safe. But if grouse chicks required long-term nest care, with all the noisy begging that entails, chances are excellent that a predator would discover and eat them.

Furthermore, grouse can lay up to 14 eggs. The male plays no role in raising the chicks, and there are too many mouths to feed for the female to manage, so the chicks need to be able to find their own food as soon as they can walk. Thus, the grouse survival strategy is for the chicks to do much of their development prior to hatching. When they emerge, they are already covered in down. They can walk and feed themselves within 24 hours. Soon they can flutter enough to reach a tree limb for safety, although two months will pass before they can fly longer distances. The hen’s primary responsibility is to show her kids how to forage and watch out for danger.

On the other hand, a great horned owl fears nothing. No predator would dare raid an owl nest when either parent is around. Females lay one to four eggs, and the incubation period lasts almost six weeks. Newly hatched chicks are sightless, featherless and helpless, and it takes another seven weeks to raise them to the point where they can leave the nest. Bald eagles spend a month incubating their eggs, followed by three months of baby-feeding. After that, eaglets may stay with their parents for up to a year before they can feed themselves independently.

[Watch: A baby loon is reunited with its parents after undergoing surgery to remove a tumor]

Other birds fall somewhere between these extremes, sometimes requiring a compromise. Loons incubate their eggs for three weeks. In that time, chicks are developed enough to swim upon hatching. However, they require another three months of development before they can fly. Most of the fowl, waterfowl and shorebird species are precocial. For instance, spotted sandpiper babies can walk within four hours of hatching. There is a tiny ledge near my house, a quarter mile offshore. I paddled out there a month ago, and found a spotted sandpiper with tiny youngsters running around. A month later, they were still there. The chicks were larger, still running, but still unable to fly far enough to leave the islet.

Watch: How to spot purple sandpipers along the coast of Maine

Most songbirds are altricial, including the warblers, sparrows, thrushes, flycatchers, swallows, woodpeckers and hummingbirds in your backyard. Their babies require constant feeding on the nest, and most youngsters continue to rely on feedings from parent birds after fledging. Flycatchers, swallows and hummingbirds are the exception. Once they leave the nest, the kids are on their own.

And thus, my backyard in July was a spectacle of hungry baby birds chasing parents. I could sit on the porch with a glass of chardonnay and watch fledglings waggle their wings in a universal begging display. There were chickadees, nuthatches, brown creepers, pine warblers, northern parulas, cedar waxwings, chipping sparrows, rose-breasted grosbeaks and red-eyed vireos flitting through the trees.

All this child-rearing activity is noisy. Parents keep the kids aware of their location. Youngsters beg. The cacophony of buzzing, squeaking and chirping is completely unlike the songs of spring. It’s subtle enough to be overlooked, but now that you know to listen for it — wow.

Bob Duchesne serves as vice president of Maine Audubon’s Penobscot Valley Chapter. He developed the Maine Birding Trail, with information at mainebirdingtrail.com. He can be reached at duchesne@midmaine.com.

 



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