You’ve heard of vampire bats. Now, discover vampire BIRDS!
When you think of blood-sucking creatures, you may imagine vampire bats or Dracula, maybe Edward Cullen, maybe even Armie Hammer the cannibal.
I doubt that ‘vampire birds’ would rank high on your list of blood-sucking creatures. But, blood-sucking birds do exist! Today, let’s learn all about them.
Meet the Vampire Ground Finch
The Vampire Ground Finch’s unassuming looks belie their blood-sucking habit: they are small; weighing under 30 grams (less than an apple) they have no vicious talons, and they have a somewhat regular beak, with no vampiric teeth.
But don’t be fooled by their demure looks: the method of a Vampire Ground Finch’s blood-harvesting is brutal! They’ll hop right up onto a another bird (usually a species called the ‘Booby’) and jam their sharp beaks violently into the seabird’s skin again and again until blood rains down. And once the vein is open, more finches congregate to feast on the source!
Like moths to a flame - or vampire finches to an open wound.
The Masked Boobies seem to endure with the pain, though. It could be because, depending on the time of year, the Masked Boobies need to stay on their nest and incubate their eggs, or care for their chicks.
The finches have no qualms pecking at either a roosting parent bird, or baby chicks, by the way!
I don’t mean to say that Vampire Ground Finches are evil: they’ve just adapted to make the best of the situation and environment they are in. For half the year, these finches use their beaks to pick at seeds, nectar and insects. It is only when the climate dries out for the other half of the year that they resort to drinking blood, in order to supplement their diet.
There's also little to no freshwater on their islands, too. During droughts, finch populations can crash by as much as 90%. Finches have resorted to harvesting blood during times of drought because they really just have no other choice.
In nature, islands are famous for being very low in resources, variety of habitats, and species. The smaller and more isolated an island is, the lower its species richness will be. This is also why many islands don’t tend to have large, land-dwelling natural predators.
With nutrients hard to come by on the Galapagos Islands, an open wound might as well be an oasis for these finches.
The finches of the Galapagos Islands are famous for how they’ve adapted. Fossil records show that only one species of finch first landed in the Galapagos, and over the years, over a dozen different finches, each with their own special way of surviving, have evolved.
Maybe you can think of it this way:
Imagine the “Lee family” moving to the U.K., with their 3 kids. When the family first moved, they began selling just one Chinese dish to the British: pork dumplings.
But with 2 adults and 3 kids each selling pork dumplings, they were competing with each other for the same market.
So, the 3 kids each branched out and began selling new dishes: let’s say, scallion pancakes, mala hotpot, and mooncakes.
Now, the Lee family - all good chefs in their own right - are getting by by utilising their skills. Yet, they’re not competing directly with each other. They have stakes in the ‘affordable food’ market (scallion pancakes and pork dumplings), ‘family reunion’ market (hotpot), and even desserts (mooncakes).
And, whenever a British person craves Chinese food, they’ll have more options, too!
Similarly, the finches that first migrated to the Galapagos Islands have since evolved different beaks to peck at small seeds, large seeds, cactus, nuts, insects, and even other birds’ blood.
But the Vampire Ground Finches aren’t the only birds with this habit. Up next, we meet the Oxpeckers!
Oxpecker birds get their names from, well, pecking oxen
There are two types of oxpeckers: red-billed, and yellow-billed. Both of them look pretty similar (except for the colours of their beaks) and both of them are ‘vampiric’.
Oxpeckers are endemic to the savannahs of Sub-Saharan Africa. There, they have a habit of perching on large mammals like zebras and cattle, and pecking at their bodies - hence their name! When you first see this bird, you may see their relationship with their large mammal host as ‘mutualistic’ - that means, you scratch my back, and I scratch yours.
That’s because oxpeckers actually mostly spend their time picking parasites off their hosts, and eating them. Parasites include ticks, small insects, and botfly larvae. In fact, the traditional swahili name for the red-billed oxpecker is Askari wa kifaru (the rhino's guard).
But in recent years, research has shown that oxpeckers are not as benign as they appear: they love opening fresh wounds on their hosts, and drinking their blood. This means that instead of having a purely mutualistic relationship with their host mammal, they may actually be in a parasitic relationship instead. (Sounds toxic!)
Do their hosts mind? (I know I would, if someone was pecking at me and feasting on my blood!)
It seems that some species do, and some don’t: Elephants and some antelope will actively dislodge the oxpeckers from their bodies when the birds land on them. Other species, like zebra, Cape buffalo and rhinoceroses, seem to tolerate oxpeckers, since the bird also search for ticks on the face.
That’s the end of today’s newsletter! I love learning about birds, and all about their unique evolutions. I hope you enjoyed reading this as much as I enjoyed writing it!