Ten facts about Red-throated Caracaras
This is a guest post by Sean McCann: photographer, naturalist, entomologist, ornithologist, and graduate student! Sean has spent a LOT of time studying among the most incredible of all the birds, the Caracaras. He kindly agreed to share 10 facts about these birds. You can follow Sean on Twitter, see his photographs on his flickr account, or follow his blog here. Unless indicted otherwise, all the photographs in this post are by Sean, and reproduced here with permission.
1) Red-throated Caracaras (Ibycter americanus) are very colourful, with red facial skin, yellow bill, a blue cere, and orange legs. They are slightly smaller than ravens. The genus name comes from the Ancient Cretan word ἰβυκτήρ (Ibukter), which means “one who begins a war song.” This name is fitting, because these birds are highly territorial and vocal, and spend a lot of time screaming at other caracaras, or humans, who invade their territories.
2) Red throated Caracaras are falcons, albeit from a very strange subfamily called the Polyborinae, which includes the caracaras and forest falcons. It turns out that falcons are not closely related to hawks and eagles, as previously thought, but rather are more closely related to parrots!
3) Caracaras are followed around the forest by a retinue of associates, including oropendolas, toucans, and araçaris. This earned them the name Capitaines des gros-becs (Toucan Captains!) in the 1800s. These other birds are thought to like hanging out with the vigilant caracaras, whose loud alarm calls may warn them of predators.
4) Unlike most caracaras, who are scavengers and generalists, Red-throated Caracaras are specialist predators of social wasps. Up to 80 percent or more of the diet provided to chicks is the brood of social wasps including some very fierce species such as Polybia dimidiata, Synoeca, and Apoica. Here's a video that shows them feeding on large nest of Polybia dimidiata.
5) Red throated Caracaras are social, often sharing large food items, travelling together in groups, and working together to defeat the defences of wasps. Red throated Caracaras are cooperative breeders (which is very unusual for a raptor) with multiple adults providing food to a single chick!
6) Red-throated Caracaras nest in bromeliads, at least in some parts of their range. In French Guiana, the two nest sites we monitored were in large Achmea aquilega bromeliads, which the birds modified for use by tearing the stiff and sharp leaves to create an open depression on the top surface. Here's a video showing nest preparation.
7) Red-throated Caracaras are highly territorial, and will attack a decoy painted to resemble them. This is how we capture them, using a decoy to lure them into a net.
8) Red-throated Caracaras also bring large millipedes to the nest, although the chick does not seem to consume much of them. These large millipedes are highly toxic, being filled with benzoquinones. Could it be that they are using these as some sort of nest fumigation?
9) Caracaras sometimes have compounds from the defensive secretions of Azteca ants on their feet. They are not likely preying on these ants, but probably get attacked by them while preying on wasps. One species of wasp, Polybia rejecta, typically nests in close association with the Azteca ants, which provide protection from army ants. Caracaras perching on a branch next to a P. rejecta nest would likely immediately find their feet covered with defensive ants.
10) Although Red-throated Caracaras are still common in South America, they are declining severely in Central America, and extirpated from southern Mexico. It is unknown why they have undergone these dramatic declines. I speculate that shooting and destruction of forest habitats may have played a role. Because of their highly cooperative breeding system, with only one chick at a time raised by up to 7 adults, they are highly vulnerable.