timelightbox:

Variable Seedeater (Sporophila corvina), 2012

Todd Forsgren ruffles feathers every time he takes a picture. LightBox presents his series of ornithological photographs of birds caught in biologists’ mist nests.

See more photos here.

ScienceDaily (May 14, 2012) — A male robin will be more diligent in caring for its young if the eggs its mate lays are a brighter shade of blue.

The blue colour in robin eggs is due to biliverdin, a pigment deposited on the eggshell when the female lays the eggs. There is some evidence that higher biliverdin levels indicate a healthier female and brighter blue eggs. Eggs laid by a healthier female seemed to encourage males to take more interest in their young.

(via Color of robins’ eggs determines parental care)

Green-headed Tanager

Young Kiwi

Kiwis are flightless birds endemic to New Zealand.  They are the smallest ratites (flightless birds) in the world and lay the largest egg in relation to their body size of any bird species currently living.  There are five recognized species, all of which are currently endangered due to habitat destruction and invasive/introduced mammalian predators.

Black & White Warbler, photo by Jimmy Kall (female, note gray auricular whereas males have black)

Hooded Warbler, by Brad Ouellette (male, note extended black helmet)

Chestnut-sided Warbler, photo by Jimmy Kall (ASY male, note the extensive chestnut on side).

biomedicalephemera:

Hieroccoccyx crassirostris - Sulawesi Cuckoo

The Sulawesi Cuckoo (usually referred to as the Sulawesi Hawk-Cuckoo, but more related to the Typical Cuckoos) is endemic to Sulawesi Island, in Indonesia. Like the other Cuckoos, this species is what’s known as a brood parasite. While a nest is unattended by the occupants, they’ll come in, lay an egg, and leave. This is then repeated with several other nests in the area, until the clutch is laid. Depending on the species, the adult cuckoo may eject the occupant’s eggs prior to laying her own, or the cuckoo chick may eject its nest mates once it hatches.

Because the chicks of brood parasites are larger and hatch earlier than the host’s eggs, they divert all attention from the host’s eggs. Birds (passerines especially) are pretty much “hey there’s a screaming chick, better feed it”, so little songbirds sometimes end up caring for and raising these big ol’ cuckoo chicks without knowing something’s off. Or maybe they do know and just can’t do anything about it, but who am I to tell? Host birds are at least clever enough that if a female cuckoo lays her egg in the nest of a bird that has differently-colored eggs from her, they other bird typically ejects the cuckoo egg and lays another clutch of her own.

Transactions of the Zoological Society of London. 1874.

Red-headed Quela (by mikesmtnfun)

Chestnut-backed chickadee

FUINHA-DOS-JUNCOS FAN-TAILED WARBLER Cisticola juncidis

(by JulioCaldas)