Helping birds build nests in my yard

Inside view of the house wren's dummy nest. I love the wren-shaped hollow in the middle!

For the second spring in a row, a male house wren used my window birdhouse to hold one of the dummy nests he showed his mate. House wrens apparently make several dummy nests for the female to choose from. Just like last year, though, she chose a different location to actually lay her eggs. Phooey! So that started me wondering whether there was anything I could do to improve the chances she might actually use my birdhouse next year. Would she prefer a different location? Or should I make better materials available for the male to use?
 

Outside view of the nest. Both years, twigs or grass stems stuck out of the entrance. I'm not sure if this is typical for the species, or just my individual bird.

As I researched house wrens’ nest preferences, I realized I could also explore other neighborhood birds’ nesting requirements. If I added more possible nest sites to my yard, like birdhouses and large bushes, and provided appropriate nesting materials, maybe I could convince even more species to nest in or near my wild back yard!

Cornell Lab of Ornithology has lots of information on birds, from how to ID them to their habitat and life histories. I looked for the species I know visit my yard in the summertime, figuring they’d be my likeliest nesters.

Anyway, my backyard birds are either cavity nesters, or branch nesters. Birdhouses can attract cavity nesters, since they look close enough to the tree holes the birds normally use. On the other hand, birds that normally build their nest on open branches aren’t likely to use a bird house. But of course birds don’t always go by the book. An ornithologist friend of mine discovered a house wren pair that was raising their young not in a cavity nest, but in an open cup nest built on some branches! Weirdos.

In doing my research, I also found that www.Nestwatch.org has downloadable plans to make birdboxes for various species too. I’m definitely adding "building birdhouses" to my project list. Maybe something to work on this winter? Nestwatch also lists helpful features of good birdhouses to guide aspiring nest hosts like me.

Cavity Nesters

A lot of birds like to nest in the hollows of dead or dying trees. Whether they add materials to the cavity, or just use the soft decayed wood that’s already there, varies by species. These birds are one of the main reasons for leaving dead trees standing in your yard when possible, rather than cutting them all the way to the ground. But if you don't have any dead or hollow trees in your yard, birdhouses make a reasonable alternative!

·       Carolina Chickadee—moss, bark strips, and hair

·       Tufted Titmouse—leaves, moss, grasses, bark strips, soft fur and hair

·       White-breasted Nuthatch—fur, bark strips or shreds, grass, feathers

·       Downy Woodpecker—wood chips

·       Red-bellied Woodpecker—wood chips

·       House Wren—twigs, feathers, grasses, hair, snakeskin

·       Carolina Wren—bark strips, grasses, leaves, pine needles, hair, straw, feathers, shed snakeskin

·       

Branch Nesters

Other birds prefer to build nests on the branches of trees or shrubs, or even under the overhang of building eaves and bridges. While you wouldn’t build a birdhouse for these species, you can still provide materials for them to use. On winter hikes, I enjoy spotting the empty nests that had been hidden during the summer.

·       Northern Cardinal—branch fork in a shrub. Uses twigs, leaves, bark, grasses.

·       Blue Jay—branch fork in a tree. Uses twigs, grass.

·       Mourning Dove—branch, also frequently nests in gutters, eaves, flowerpots. Uses twigs, grass, and pine needles.

·       House Finch—tree branch, also structures like hanging flowerpots, vents, & streetlamps. Uses fine stems, leaves, twigs, and feathers.

·       Eastern Goldfinch—branches in a shrub. Uses spider silk, plant fibers, and fluff from seeds like dandelion and thistle.

·       Eastern Phoebe—under the overhang of building eaves or under bridges, especially near running water. Uses mud, moss, leaves, grass, and animal hair.

·       Northern Mockingbird—Shrubs. Uses twigs, grasses, rootlets, and leaves.

·       American Robin—horizontal tree branch, or on/under structures like eaves, gutters, and light fixtures. Uses twigs, grass, feathers, and mud.

You might have seen suggestions to provide bits of string and yarn or even dryer lint for nesting birds. When I was a kid, we often draped scraps of yarn on bushes outside, in hopes that birds would weave them into their nests. But it turns out string and lint aren't actually safe or useful for the birds. Dryer lint turns hard and crumbly once it’s gotten wet, rather than staying soft or helping hold the nest together. And even short bits of yarn can tangle around baby birds’ feet and toes. I don't want to hurt or endanger the baby birds in my yard, so I won't be using yard scraps for my nest material kits.

Some of the nest materials I listed are already available in my yard, like the drifts of dry leaves that collect in corners. Others I will tuck into clean, empty suet feeders to make little supply stations for inquisitive birds, as described here. I don't put out suet in the summertime, so the suet cages are available for use. Fat can go rancid in the Maryland heat, and softened fat could also foul a bird's feathers. So next spring, I'll stuff the cleaned cages with materials like bark strips, dry grasses, plant fluff and odd feathers. I have lots of milkweed plants in my yard, and plan to collect some of their seed fluff when the pods ripen this fall.

In the long term, I also want to add more shrubs and bushes to my property. I have a back yard that's mostly underutilized in terms of gardening-- it has a few trees that were already there when I moved in, but I haven't changed things very much beyond adding the log pile. The back is partly to mostly shady, so isn't conducive to most pollinator plantings. But birds don't need the sun quite as much as bees and butterflies and flowers do. So I might focus my back yard landscaping on bird habitat. Stay tuned! 

Do you have any birds nesting nearby this year? Have you discovered birds nesting in odd places? I'd love to hear about them in the comments!

The wren mostly used twigs this year, but also some tall grasses complete with seeds. Handy snacks, perhaps?