![]() In keeping with their ecological opportunism, it follows that the finches don't only take advantage of the blood of seabirds. The blood-feeding behaviour was first observed (so far as we know) in 1964, and published in 1965 (Bowman & Billeb 1965). It is also unusual in feeding on nectar and on breaking into booby eggs to drink their contents. Unsurprisingly it is therefore sometimes known as the Vampire finch. septentrionalis alone that feeds on blood, and it does this by pecking at the feather bases of boobies. debilirostris of Fernandina and Santiago, G. 2000), and three subspecies are recognized: G. difficilis appears to be the oldest of the ground finches (Petren et al. ![]() By far the most variable of all Darwin's finches in both morphology and diet, G. Interestingly, the only low islands it occurs on are those where the highly similar Small ground finch G. difficilis occurs in the highlands of the large central islands of the Galapagos as well as the low islands Genovesa, Darwin and Wolf. I will however repeat that oft-uttered complaint that the birds would perhaps be better named Gould's finches, given that John Gould (1804-1881) is the one who first described them and thereby brought them to scientific attention. Here I'm going to try really hard to not veer off at a tangent and talk about any one of the many, many interesting things that could be said about these finches and their discovery, diversity, evolution and ecology. It's one of the Darwin's finches of the Galapagos, the Sharp-beaked ground finch Geospiza difficilis. ![]() This raises the question that some of you have already been asking: was a similar path followed by the ancestors of vampire bats? Well that's a very good question, and we'll come back to it shortly-ish.Īs I've hinted a few times - and as you probably know (well done you) - Redbilled oxpeckers are not alone among passerines in being part-time parasites: another species that sometimes picks ectoparasites from larger animals also practices vampirism, and even without this behaviour it's already a well-studied and highly interesting bird. blythii, are facultative removers of ectoparasites on such hoofed mammals as zebras, donkeys, camels, ibex, klipspringers, domestic cattle and giraffes (Feare & Craig 1998, Fennessy 2003). tristramii and Somali red-winged starling O. Oxpeckers are apparently highly specialized starlings, and we know that other starling species, namely the Pale-winged starling Onychognathus nabouroup, Tristram's red-winged starling O. slooooths), and trumpeters may pick parasites from the fur of brocket deer (Peres 1996). This behaviour is pretty widespread: Fan-tailed ravens Corvus rhipidurus may groom camels, some drongos glean ectoparasites from giraffes, Black-billed magpies Pica pica have been observed grooming moose, some bulbuls groom klipspringers, some caracaras clean tapirs and sloths (mmm. The first stages in this process are perhaps illustrated by the various bird species that, on occasion, remove ectoparasites from the bodies of large mammals. But how did the wound-feeding start? Presumably the birds first started crawling around on big mammals to eat the associated insects, then later started to take advantage of snot, or earwax, and then learnt that blood and skin were even more nutritious. ![]() If they did do that, then we would at least know how sanguivory, or haematophagy, or vampirism, or whatever, did evolve within this group: they would have started by wound-feeding, and later switched to wound making. At the moment they seem not to be in the habit of making their own wounds in order to feed, but it's not so far-fetched to imagine that they might learn this ability in the future. If I were to indulge in one of those credibility-destroying rampant speculations about a possible future course of evolution, I might speculate that Redbilled oxpeckers are on their way to specialized and dedicated vampirism. So Redbilled oxpeckers ( at least) are (sometimes) wound-feeding, blood-eating parasites (and before reading the following you need to see the previous posts here and here). Yet more musings on the evolution of blood-eating in passerine birds. ![]()
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