American Coot - Fulica americana - Chick

Wrote recently about the American Coot (see Blogspot and scroll down:http://lenblumin.blogspot.com/), so today I'll let you enjoy the very young chicks that we saw swimming along Marble Hot Springs Road in the Sierra Valley. A parent was nearby and occasionally brought food to one of the 3 youngsters. Not sure if they are called "chicks", or maybe "cootlets"?

The first shot shows one of the chicks fluttering its just emerging wings, just the way passerine chicks will beg. I presume the coot young are semi-precocial. They clearly leave the nest and swim soon after hatching, but perhaps are fed by the parent for a short period of time. Wonder if anyone has speculated about why the chicks have such bright head color - maybe the parents don't have good vision?!

Regarding the color of the American Coot chick, I found an interesting explanation on Wikipedia:

Much research has been done on the breeding habits of American Coots. Studies have found that mothers will preferentially feed offspring with the brightest plume feathers, a characteristic known as chick ornaments.[4]

Davies, Nicholas B.; John R. Krebs and Stuart A. West (2012). "8". Behavioural Ecology. West Sussex, UK: John Wiley and Sons.

[further]

Chick ornaments The first evidence for parental selection of exaggerated, ornamental traits in offspring was found in American Coots.[27] Black American Coot chicks have conspicuously orange-tipped ornamental plumescovering the front half of their body that are known as “chick ornaments” that eventually get bleached out after six days. This brightly colored, exaggerated trait makes Coot chicks more susceptible to predation and does not aid in thermoregulation, but remains selected for by parental choice. These plumes are not necessary for chick viability, but increased chick ornamentation increases the likelihood that a chick will be chosen as a favorite by the parents. Experimental manipulation of chick ornamentation by clipping the bright plumes have shown that parents show clear preferences for ornamented chicks over non-ornamented ones.[27]

American Coot - Fulica americana

In winter the San Francisco Bay Area hosts many thousands of American Coots, Fulica americana, seen just about anywhere you find a significant collection of water. We see rafts of up to 1,000 on Richardson Bay, for instance. By the end of May many have departed to find secluded marshes to build nesting platforms, but a few remain here to breed (the young have amazing red heads!). This bird was at Las Gallinas in March, and although I don't often photograph Coots (they are difficult subjects for technical reasons) I did like the way the light brought out the red color in the iris and the claret-brown color of the button callus button on the white frontal shield. The also have a black ring near the tip of the bill, sort of like the unrelated Pied-billed Grebe.

The "shield" is an unusual fleshy structure that extends upward from the tissue of the upper mandible to cover a portion of the forehead. Function uncertain, but speculation includes protection, as well as use in individual identification and in breeding display. The shield, and the pigmented button of callus near the top, vary a lot with age and sex and the shape has been used to differentiate individual coots.

Taxonomy:

The Coots are in Gruiformes, a diverse order includes 11 different families of birds.

Family: Railidae - Rails, Gallinules, Coot and Crake - 135-140 species in all.

Other gruiform families (# species) include: Limpkin (1), Cranes (15), Mesites (3), Buttonquail (16), Cranes (15), Trumpeters (3), Finfoots (3), Kagu (1), Sunbittern (1), Seriema (2), and the Bustards (26). Some birders like to try and see all the families of the world (numbering around 230), so the Gruiformes provide them with some good targets.

Genus: Fulica - The Coots, 11 species in all - 9 of them seen in the Americas. Our only Coot is the American Coot, unless you count the Hawaiian Coot, which is indeed a separate species.