Bird nests: Keepers, throwers or fixer-uppers
- John Lorson: The Rail Trail Naturalist
- July 9, 2021
- 1236
A testament to a well-built nest, this woven structure above the doorway of a local church has hosted a mourning dove, who settles in to incubate her eggs in the largely unaltered nest built and occupied by an American robin in spring 2020. While the robin will likely build new each season, the dove apparently knows a good deal when it sees one.
It was the week between Christmas and New Year’s Day, and I was about to witness an impressive example of heavy-duty nest building in progress.
The temperature stood at a brisk 30 F, and I had just rolled away from the relative comfort of a stretch of tree-lined trail to punch my way into a substantial headwind where the Holmes County Rail Trail is bordered on both sides by flat, empty fields. Wind is the worst part of winter bicycle riding, and crouching under it while grumbling about the lack of a respectable windbreak, I darn near missed the show of the day. Luckily, I lifted my head just in time to see a bald eagle cross the trail at treetop height just 30 yards ahead of me.
The bird looked for a moment as if it was about to land on an old ash snag beside the trail, but as I watched, the very branch the bird was set to alight suddenly gave way, breaking from the tree. The eagle, without missing a beat, wrapped both sets of talons around the falling branch, which looked to be about 4 inches in diameter and every bit of 6 feet long, powered up a bit to regain altitude and delivered the material straight to the towering bowl of its nest beside Killbuck Creek. Nest building in December — who would have imagined?
As is the case with many species, the size of the bird dictates the size of the nest. An eagle’s nest is typically 5-9 feet in diameter, several feet deep and may weigh well over a thousand pounds. An effort like that deserves more than one use, and the eagles tend to oblige, using the same nest year after year, adding branches here or there to shore up the structure.
That the bird’s efforts were taking place so early in the season was a testament to the long incubation and fledgling periods of the enormous bird. Eagles expend a huge amount of effort in prepping the nest and raising just a single brood of two or three chicks per year. The fact that much of their occupancy takes place in cold or cool weather likely helps to keep pests and parasites to a minimum.
Smaller species — many of the songbirds for instance — not only hatch multiple broods per year, but also may actually build a new nest for each brood, looking to stay ahead of infestations of lice and mites that lay their own eggs in the nest just as the birds. Wary birds also will relocate between broods to keep predators guessing. It’s not unusual to find a nest that has fallen to the ground at this time of year, and while one’s first intuition may be to imagine some sort of tragedy has befallen the young, it’s good to keep in mind some birds have fledged their third brood of the season by this time of year.
The American robin, one of the first birds many children in the Midwest are introduced to because of its legendary place as a harbinger of spring in children’s literature, will raise multiple broods and may create more than one nest in the course of a season. Its nest, a woven structure typically the size of a soup bowl, tends to be durable and long-lasting. And while a robin might choose to move on for whatever reason, another bird may well take up residence once the original builder has left.
Even if a nest is completely abandoned, it’s never a total loss. The structure may be scavenged for materials by other birds or even small rodents. Nature, when left to its own devices, is the ultimate recycler. Nothing ever goes to waste.
Remember, if you have comments on this column or questions about the natural world, write The Rail Trail Naturalist, P.O. Box 170, Fredericksburg, OH 44627, or email jlorson@alonovus.com. You also can follow along on Instagram @railtrailnaturalist.