Where do birds nest?

Birds nest in all kinds of places!
Where a bird builds its nest depends on the bird species.

Different species of birds nest in different kinds of habitat, at different heights, and at different times. Some birds nest in trees, bushes, under bridges, on balconies, in the ground, on cliff sides, nest boxes, and many more places.

For example:

Ovenbird Nest by Barbara Powers

• Ovenbirds create their nests in the ground (it looks like a Dutch oven –with a side entrance). 

•  Pigeons make a very flimsy nest (sometimes they add no nesting material at all and lay their eggs on bare ground) They might lay their eggs on an air conditioning unit on the window of a city building or on the floor of a balcony.
   
• Killdeer lay their eggs right on the ground. They might lay their eggs on building rooftops, gravel parking lots, or a baseball field.

NOTE: although this video is shown for educational purposes, please enjoy nature from a distance. When people get too close nesting birds, it puts unnecessary stress on the birds.

Gravel rooftops attract Killdeer for nesting, but they can be dangerous. Chicks may be unable to leave a roof because of high parapets and screened drain openings. When adults lure chicks off the roof, the chicks may die from the fall. However, some chicks have been observed leaping from a seven-story building and surviving!

• Mourning Doves usually build their nests in trees but will build them on the ground, on window ledges, or on other man-made structures if needed. The male looks for a good place to build the nest, once he finds a good place he calls the female and she either approves or disapproves. Once they choose a site the male finds small twigs and delivers them individually to her by standing on her back. She arranges them around her and uses her body to make a simple bowl. The male might make 30–40 trips at a time to give the female nesting material (normally in the early morning). 

• Hummingbirds build tiny nests. They are built by the female alone in trees (oaks, birches, pines), bushes, or other more interesting places like loops of chain or wire. Males and females only come in contact while mating. Scientists think that females find the place to build the nest, build the nest, incubate the eggs, and raise their young without any help from the male.

Anna's Hummingbird photographed by Jack Lowell

• Robins might take 5-7 days to build their first nest.  Most raise a second brood during the breeding season, which can fledge just 5 weeks after the first!  The second time a robin builds a nest it might take only 2-3 days, and rarely robins will have to build a third nest, which they can do in one day, but this is unusual. 
  

American Robin with nesting material, by Meena Haribal, Ithaca, NY	Robin nest built on tires 9 days in a row at I-77 N Welcome Center, Dobson,  North Carolina, by Jeff Mills

Did you know?

Brown-headed Cowbirds don’t make nests. Instead they lay their eggs in the nests of other bird species, who then raise the young cowbirds.

Book recommendation: A great book about where birds nest is: Urban Roosts: Where Birds Nest in the City by Barbara Bash (Author), Sierra Club Books (Author)

How do birds mate?

Although some birds may have long and involved courtship displays, it does not take long to actually mate. Mating (the transfer of sperm from the male to the female) is very brief and  takes place by the coming together of the two birds' 'cloacas'. During the breeding season, the area around the cloaca becomes swollen and reaches its peak size when the time is just right to reproduce. Sometimes it is called a "Cloacal Kiss".

When bird banders catch a bird in their nets they "sex" it by blowing on the bird to part the feathers to see if the cloacal protuberance is visible during the mating season. Males have an enlarged cloacal protuberance.

Birds often have interesting courtship rituals. Learn about Pigeon Courtship behaviors.

Some of these behaviors include:

(Illustrated by Julie Zickefoose)

Some birds have spectacular courtship displays. Scientists think that Bald Eagles find a mate and stay together for life unless one mate dies. When they are courting they do incredible acrobatic flight displays. One display is called the "Cartwheel Display":  the pair fly very high, lock talons, and tumble/cartwheel back toward earth. They let go of each other only at the last moment to avoid crashing with the ground. Watch an aerial courtship display by Bald Eagles:

How long does it take to grow wings?

A bird grows in the egg while the parents incubate it (sit on it) and then continues to grow after hatching until it is ready to fly. Some birds can leave the nest almost instantly (as soon as they are dry after hatching), but still cannot fly until they are ready (approximately one month later).  Other birds don’t leave the nest until they are ready to fly.

• Pigeons incubate their eggs for about 18 days. Once they hatch they fly from the nest for the first time after approximately 30 days.
• Peregrine Falcons fly about 40 days after hatching
• House Sparrows fly approximately 12 days after hatching
• Brown-headed Cowbirds fledge about 10 days after hatching

Young birds don’t just have to ‘grow’ their wings, they have to exercise them, and prepare themselves to fly for the first time. It’s not always easy!