Ah, Spring is here, the birds are singing, mating, nesting and birthing their babies. I thought it might be fun to learn a bit more about the whole process, so I headed over to the Cornell Lab of Ornithology's NestWatch site where I borrowed most of the information included here. I also scoured the web for interesting bird details and have included those, too.
Alas, I don't have any personal photos of nests and eggs and babies, but I do have photos I've taken of some waterfowl babies, so I'm sprinkling those in here so you can have some moments of joy from the cuteness of them. The title photo above is an adorable little something. To add some fun to this Dawn Chorus, I'm going to let you put down your guesses as to what these babies are in the comment section.
FUN FACTS:
More than 700 bird species breed in North America, and the variations in their behaviors are fascinating and complex. Different species find mates, build nests, lay eggs, and raise their young in incredibly different ways.
The chicks of large bird species often take the longest to hatch. Emu chicks, for example, take 60 days to hatch. Small songbirds take just 2 weeks.
The bird that lays the smallest egg in the world is the bee hummingbird. Its egg is just under 0.5" x 0.25" and weighs a mere 0.02 oz.
The ostrich lays the biggest egg in the world. It measures 7" x 5" and weighs 3 pounds. However, the biggest egg for the size of the mother is laid by the kiwi and is a third of the weight of the bird. It is 5" long and can weigh as much as 1 lb. This would be the equivalent of an ostrich laying an 88 lb. (40 kg.) egg.
Throughout the year, most birds use day length to tell what season it is. When the number of hours of daylight exceeds a certain critical level, physiological changes are triggered in birds which prepare them to breed. Most birds, especially those in temperate regions, also time their breeding activities so that they will be feeding their nestlings when food is most abundant. However, well before nestlings arrive, birds need to select a breeding territory. Non-migratory species may either maintain a territory throughout the winter or establish a new one in the spring. Migratory birds begin looking for and defending a territory as soon as they arrive in the spring. Good territories provide potential nest sites, reliable food sources, and protection from predators.
The total number of eggs that a female can lay in one nesting attempt varies widely depending on the species. For example, many tropical birds lay clutches of only 2 or 3 eggs. Waterfowl, such as Wood Ducks, can lay up to 15 eggs in one nesting attempt. Clutch size can also vary widely among individuals of the same species depending on food and calcium availability, latitude, the age of the female, weather, and time of year. The size, shape, color, and texture of bird eggs are also extremely variable both within and among species.
Birds incubate their eggs to keep them at the proper temperature to ensure normal development. Female songbirds usually begin incubation after they have finished laying all of their eggs so that they will hatch at approximately the same time. Other birds, such as herons, cranes, cormorants, and raptors begin incubation as soon as the first egg is laid and therefore their eggs may hatch on different days. In some species, like Black-headed Grosbeak, both males and females incubate eggs. Incubation time varies depending on the species, but typically the larger the bird, the longer the incubation period.
Songbirds and most seabirds have altricial young, meaning that the newly hatched birds are blind, featherless, and helpless. Immediately after hatching, altricial birds can do little more than open their mouths to beg for food. They remain in the nest where the parents can feed and protect them while they continue to develop. For the first week of life, most altricial birds cannot control their own body temperature and must be constantly brooded (kept warm) by their parents. By the end of the first week, their eyes are usually open and their feathers are beginning to emerge. During this period, nestlings can experience remarkable growth by doubling their body weight several times! Precocial species, such as ducks and many shorebirds, are born fully feathered, mobile, and with eyes open. Incubation periods are longer for precocial birds than altricial birds, allowing for increased embryonic development in the egg, and therefore they have relatively advanced motor and sensory functions at hatching.
To keep up with the food demands of nestlings, their parents continuously forage for food. This is an extremely dangerous time for both the adult and young birds because the increased activity and begging cries of nestlings can attract predators. After 2 or 3 weeks, most songbirds are usually ready to leave the nest. Other birds, such as raptors, may stay in the nest for as long as 8 to 10 weeks. In contrast, precocial birds spend hardly any time in the nest and are often seen wandering in search of food alongside their parents only hours after hatching.
Nesting success is often related to the quality of habitat within a bird’s territory. Habitat quality is the ability of the environment to provide the appropriate resources, such as food and shelter, to enable individual and population survival. Generally speaking, the higher the habitat quality is in your backyard, farm, or local park, the better these places will be able to support nesting birds. NestWatchers can help increase the number of birds nesting and young fledging by making bird-friendly improvements to the landscape!
SOME BIRD-FRIENDLY IMPROVEMENTS INCLUDE:
There are many more ways to cultivate habitat by gardening or landscaping for birds on your property! To learn more about land stewardship for birds, visit our sister project Habitat Network, where you can map an area’s vegetation types, read articles on improving habitat, and share local knowledge with other citizen scientists near you! Habitat Network is dedicated to providing tools for you to make better decisions about how to manage landscapes sustainably.
Now, a little more nesting details on eggs laid and length of incubation.
Clutch Size & Phenology for Common Species
Estimates are based on The Birds of North America Online and Nests, Eggs, and Nestlings of North American Birds – Second Edition by Paul Baicich and Colin Harrison.
Species |
Average Clutch Size |
Average Incubation Period (in days) |
Average Nestling Period (in days) |
Acadian Flycatcher |
3 |
14 |
12 |
American Crow |
4-5 |
18 |
35 |
American Goldfinch |
5 |
13 |
14 |
American Kestrel |
4-5 |
30 |
30 |
American Robin |
4 |
13 |
15 |
American Tree Sparrow |
3-5 |
13 |
10 |
Ash-throated Flycatcher |
4-5 |
15 |
17 |
Bald Eagle |
2 |
41 |
75 |
Baltimore Oriole |
4 |
13 |
13 |
Barn Owl |
4-6 |
31 |
32 |
Barn Swallow |
4-5 |
13 |
21 |
Barred Owl |
2-3 |
31 |
32 |
Bewick’s Wren |
5-7 |
14 |
14 |
Black Vulture |
2 |
36 |
62 |
Black-capped Chickadee |
6-8 |
13 |
25 |
Blue Grosbeak |
4 |
12 |
11 |
Blue Jay |
4-5 |
17 |
19 |
Blue-gray Gnatcatcher |
4-5 |
15 |
13 |
Bobolink |
5-6 |
12 |
12 |
Boreal Chickadee |
4-9 |
14 |
18 |
Brown Thrasher |
4-5 |
13 |
11 |
Canada Goose |
5-6 |
28 |
5 |
Carolina Chickadee |
6 |
13 |
17 |
Carolina Wren |
4-6 |
13 |
13 |
Cedar Waxwing |
3-5 |
13 |
17 |
Chimney Swift |
4-5 |
19 |
19 |
Chipping Sparrow |
4 |
13 |
11 |
Dark-eyed Junco |
3-5 |
13 |
12 |
Downy Woodpecker |
4-5 |
12 |
21 |
Eastern Bluebird |
4-5 |
14 |
17 |
Eastern Phoebe |
5 |
15 |
16 |
Eastern Screech-owl |
4-5 |
26 |
31 |
Eastern Towhee |
3-4 |
13 |
9 |
European Starling |
5-7 |
14 |
21 |
Field Sparrow |
3-5 |
11 |
8 |
Gray Catbird |
4 |
13 |
11 |
Great Blue Heron |
4 |
27 |
77 |
Great Crested Flycatcher |
4-5 |
14 |
15 |
Great-horned Owl |
2-3 |
31 |
34 |
Hairy Woodpecker |
4 |
13 |
29 |
House Finch |
4-5 |
13 |
15 |
House Sparrow |
3-5 |
13 |
15 |
House Wren |
6-8 |
14 |
15 |
Indigo Bunting |
3-4 |
13 |
11 |
Killdeer |
4 |
25 |
precocial |
Lesser Goldfinch |
4-5 |
12 |
11 |
Mallard |
10-12 |
28 |
precocial |
Mountain Bluebird |
5-6 |
14 |
20 |
Mountain Chickadee |
6-12 |
14 |
21 |
Mourning Dove |
2 |
15 |
14 |
Northern Cardinal |
4 |
12 |
10 |
Northern Mockingbird |
3-5 |
13 |
13 |
Osprey |
3 |
33 |
55 |
Pileated Woodpecker |
3-5 |
18 |
27 |
Prothonotary Warbler |
4-6 |
13 |
11 |
Purple Martin |
4-5 |
16 |
28 |
Red-eyed Vireo |
4 |
13 |
12 |
Red-tailed Hawk |
2-3 |
30 |
30 |
Red-winged Blackbird |
4 |
11 |
11 |
Rose-breasted Grosbeak |
4 |
13 |
11 |
Ruby-throated Hummingbird |
2 |
16 |
19 |
Say’s Phoebe |
4-5 |
13 |
15 |
Song Sparrow |
3-5 |
13 |
10 |
Spotted Towhee |
3-4 |
13 |
9 |
Tree Swallow |
4-6 |
15 |
20 |
Tufted Titmouse |
5-6 |
13 |
17 |
Turkey Vulture |
2 |
39 |
77 |
Violet-green Swallow |
4-5 |
14 |
24 |
Western Bluebird |
4-6 |
14 |
20 |
Western Screech-owl |
2-4 |
26 |
28 |
Western Scrub Jay |
2-3 |
16 |
18 |
Wild Turkey |
8-12 |
28 |
precocial |
Wood Duck |
8-10 |
30 |
precocial |
Wood Thrush |
3-4 |
13 |
13 |
Finally, here’s a fun little video of ducklings, geese and chicks. Use the comments section to add your answers on photo ID by number and I’ll provide the correct answers if folks are stumped. Feel free to use this as an Open Thread to tell us what’s going on in your birding world. And you have any nest, egg or baby bird photos to share, please add them!