Spring is upon us, with leaves of deciduous trees, blooming flowers and warming temperatures. For birds, this means that two things are imminent: migration and nesting.
Summer birds like swallows and orange-crowned warblers are already showing up from the south, while winter birds like crowned sparrows will soon head north. A few birds that nest particularly early in the year, such as hummingbirds and owls, may have already established their nesting sites during the first few months of the year. But for the majority of songbirds, the great drama of nesting season has only just begun.
The birds concentrate their breeding activity in the spring and summer when food is most plentiful, the weather is less harsh, and there are many hours of daylight for feeding. Early spring – March and April – are the peak months for birdsong, one of the highlights of the year. As we move into summer, the song will gradually diminish as the birds move out of that earlier stage of attracting mates and declaring territories, and into a calmer stage of the season where keeping a lower profile is the best way to keep eggs and baby birds safe.
May and June are the best months to see fledglings, with second broods and late-nesting birds still raising young in July and August.
What does nesting season look like right now? Strong. Hear the “teewee, teewee, teewee” chirping of chickadees and dry trills and even juncos in local forests, the propulsive tinkling of spotted towhi and the loud staccato punctuation of the musical hum of Bewick’s wrens in scrubby habitats and long chirping songs of house finches and goldfinches in almost any garden. Mourning doves perform their namesake “coo-AHHHH, coo, coo, coo” as males announce their unpaired status, and mockingbirds sing their incredibly varied combinations of original sounds and imitations every hour of the day ( and often at night).
Depending on the species, singing may be the most important means of declaring territory to rival males or demonstrating health and fitness to potential mates. Soon the main events of the season will come: a week or two of building the nest, a week or two of laying, two or three weeks of incubating the eggs and another two or three weeks of caring for the chicks before they fledge. The exact timing of each stage will vary depending on the bird in question, but when compared to us, one thing is universally true: baby birds grow rapidly.
If you don’t want to miss the brief wonders of birds’ childhood, your best tool is a birdhouse or birdhouse. Installing a birdhouse is easy to do, with little ongoing maintenance or expense for bird feeders. Be aware that only some birds nest in houses, while the majority of songbirds build open nests in trees.
Nest boxes serve so-called “cavity-nesting” birds that seek holes in trees for their nest sites, either naturally formed or dug by woodpeckers. In Marin this mainly means chickadees, wrens and chickadees in areas with tree cover and bluebirds and swallows in more open areas. With larger specialized houses, you might also attract northern owls and spotted owls in woodland habitats or barn owls near open hunting areas like agricultural areas, fields, or wetland edges.
That’s what nest boxes are. Now some practical advice on how. A common mistake is to place a house next to bird feeders – instead place it as far away as possible. A nest box is a nursery for vulnerable, helpless chicks and parent birds seek a secret, secluded area away from potential dangers like jays or humans.
Other key steps to success are setting up the house securely (rather than letting it hang and swing freely), lifting it at least a little off the ground (6 feet or more is a good rule of thumb), and s Make sure the entry hole is large enough (1 1/2 inches is the correct size for a general purpose songbird box).
Finally, get up quickly. The first nesting species have already found their nesting sites and the others are not far behind.
Jack Gedney’s On the Wing airs every other Monday. He is co-owner of Unlimited Wild Birds to Novato and author of the forthcoming book “The Private Lives of Public Birds.” You can reach him at firstname.lastname@example.org.