The Yellow-billed Cuckoo nest that was first described in this post from a few days ago now has two scraggly nestlings. Despite the mid-morning heat, an adult was incubating them when I arrived. These nestlings are about 4-5 days old, which indicates that hatching began shortly after my last visit on May 30. Bendire’s description of the young from 1895:
“The young when first hatched are repulsive, black, and greasy-looking creatures, nearly naked, and the sprouting quills only add to their general ugliness”
These younglings may not be the most aesthetically pleasing bird babies that I’ve ever seen but I like ’em. They made amusing hissing and spitting sounds, which seemed to fit their general appearance and the character of their parents. There were three eggs on May 30 so I’m not sure what became of the third. Amazingly, these nestlings will resemble full blown Yellow-billed Cuckoos in just a day or two, which means this will likely be the last check on this particular nest.
Nidiologicals – Peck and James (1987) and Hughes, J.M. (1999)
Habitat – Open woodland habitats with clearings and dense shrub cover. Microhabitat – Nest concealed by foliage on outer branch or main fork of tree or shrub. Spring arrival – Early to late May (Ontario) Average nest height – 1m-2m (Ontario) Nest builder – Male and female Average # of broods/season – 1 (multiple broods may occur when food sources abundant) Average egg laying date – 9 June-4 July (Ontario) Average clutch size – 2-3 eggs Incubation period – Average 9-11 days Egg colour – Unmarked pale bluish green. Incubation – Male and female Brown-headed Cowbird host – Yes
The cuckoo family (Cuculidae) is a diverse group of over sixty species that inhabit all continents of the globe except for Antarctica. The Yellow-billed Cuckoo, like its relatives, has an unusual and complex breeding system. Yellow-billeds are non-obligate brood parasites, meaning that they will tend to their own nests but also lay eggs in nests of other birds, especially when food sources are abundant. They will deposit eggs in other Yellow-billed Cuckoo nests (intraspecific parasitism) but also target Black-billed Cuckoo, Wood Thrush, Gray Catbird and American Robin (interspecific). These species lay eggs that are most similar in appearance to their own (unmarked blue to greenish), thus suggesting egg-mimicry is involved.
Male and female Yellow-billed Cuckoos build their nests within a few metres of the ground, usually in areas with a dense shrub layer. Nests are loosely constructed platforms composed of twigs and sparsely lined with dried leaves, plant tendrils and bark strips (Hughes 1999). The nest pictured above was discovered on May 25, 2010. The lining of this nest included fresh leaves while a sprig of Reindeer Lichen was added later. Both sexes incubate but the male brings new material to the nest when subbing in for the female. There is a vast list of fascinating factoids about Yellow-billed Cuckoo nests but I was particularly struck when I read that young are reared from egg to fledgling in just 17 days! This particular observation is astounding….
At age 6-7 d (26-29 g), feather sheaths burst open; nestling methodically preens off sheaths with bill; within 2 h nestling is fully feathered, but tail is still short (Hughes 1999).
This almost supernatural feather growth is colourfully described by Dr. A.H. Cordier in 1932 as follows:
The first picture was made at nine o’clock. . . . This shows the young by the unhatched egg; the horny, sheathed feathers were fully two inches long, making the bird look like a porcupine. About ten-thirty the sheaths began to burst, and with each split a fully formed feather was liberated. This process took place with such rapidity that it reminded me of the commotion in a corn popper or a rapidly blooming flower. All the while I was within three feet of the bird, and could see every new feather, as it blossomed, so to speak.
At three p.m., six hours after the first picture was taken, I made another photograph, showing this same bird in the full plumage of a Cuckoo, except the long tail.
I will be back to this nest very soon to check on its progress and also to sneak a peek at the young, which were described by Bendire in 1895:
The young when first hatched are repulsive, black, and greasy-looking creatures, nearly naked, and the sprouting quills only add to their general ugliness
This is the first Yellow-billed Cuckoo nest for our project but probably not the last. Both Yellow-billed and Black-billed Cuckoos are regular breeders throughout the Frontenac region. While much of the region is heavily forested with mature deciduous woods that are normally avoided by cuckoos, clearings created by wetlands, rock outcrops and ridgetops are abundant. Here in the arch, it is plausible that the Yellow-billed Cuckoo is yet another species benefiting from the rugged southern shield topography, low-intensity agricultural practice, shallow till and historical fires.