For a large portion of birdwatchers we have entered a time of year when birding activity noticeably slows and those 5 AM wakeups are put behind them. The chaos and excitement of migration is over and other priorities rise to the top of our agenda. Kids’ soccer games, lake visits, and yard work have replaced trips to the favorite wetland or woods. That leaves a few of us still curiously observing nesting birds.
Most of our songbirds are busy either building nests, sitting on eggs, or rearing young. These can be fascinating processes to watch and take note of.
The year starts early, of course, with great horned owls and bald eagles laying eggs, most often with snow still on the ground. But we are in the chaotic midst of bird breeding right now with most of our songbirds.
Nests themselves are a thing of wonder. The variety and habits among the different species is all over the map.
Many seabirds, for instance, build no nest at all, preferring to lay their eggs on bare rock. Locally, similar behavior can be observed among such species as killdeer, which place their eggs on almost any piece of bare ground such as gravel roads, roof tops, or even mowed lawns.
Most of us are familiar with woodpeckers, which excavate cavities in dead wood to be used for egg laying. Ultimately these holes are used again and again by other cavity nesters like black-capped chickadees, nuthatches, or wood ducks.
Songbirds, for the most part, are our classic nest-builders with American robin being an ideal example.
Its nearly perfect bowl of grassy sprigs smoothly lined with mud is known to children and adults alike given their near fearless propensity to breed near human structures. I’d be willing to bet there isn’t a person among us that hasn’t seen a robin nest on a house light, on a downspout, or some similar structure.
Nest materials vary almost as much as nest types. For instance great crested flycatchers (another cavity nesting species) often incorporate shed snake skin into the nests. As to why, no one really knows. But these days the species seems to have modernized a bit as pieces of plastic bags are sometimes used in lieu of snake skin. Swallows are well known to line their nests with feathers shed from other species. It is thought this is intended to insulate the young birds from cold temperatures.
Most songbirds have, by now, already fledged from their nests. Large flocks of common grackles and red-winged blackbirds are noticeable in the area with many juveniles among them. However, a lot of songbirds will nest more than once a season and are sitting on their second set of eggs.
Making observations this time of year somewhat challenging is the thickness of green growth everywhere. Nests placed high up in trees, for instance, are nearly impossible to monitor among the leaves. Instead, pay attention to behaviors.
There are clues that careful observers can use to verify the presence of a nest. Returning continually to the same spot is one. Birds seen carrying nest material like grass or twigs is another. Birds defending an area from intruders is still another solid hint that a nest is nearby.
My favorite is food-carrying. Generally food is not carried in flight by birds, raptors being the obvious exception. If a songbird is witnessed carrying a caterpillar or similar food item, you can be confident that they are heading to a nest to feed young birds or possibly a mate.
A few of us witnessed this last weekend when we spent some time in southeast Minnesota looking for area specialties. Quite rare to Minnesota, a prairie warbler had been documented in a spot near the Iowa border. We found the bird without too much difficulty. But making this sighting highly important was the fact we observed the male carrying food, thereby verifying a nesting attempt.
While this may not be the season for “oh wow” numbers of migrant birds, studying nesting activity among the species that are here can provide many hours of interesting and informative observations; observations that are important to understanding the range and distribution of these fascinating animals.