Friday, July 30, 2010

A Little Lunch

Little Owl

I looked up “cannibal” on the Internet after Will sent me some photographs.

“A cannibal is an animal that feeds on others of its own species but it is not an unnatural characteristic: more than 140 different species have been found to show cannibalistic tendencies under various conditions.

Sexual cannibalism has been shown in for example the female Red-back Spider, Black Widow Spider, Praying Mantis, and in scorpion species where the female eats the male after mating. The more common form of cannibalism is size structured cannibalism, in which large individuals consume smaller ones. Such size structured cannibalism has been observed in the wild for a variety of taxa, including octopus, bats, toads, fish, monitor lizards, salamanders, crocodiles, spiders, crustaceans, mammals, and a vast number of insects, such as dragonflies, diving beetles, back swimmers, water striders, flour beetles, caddis flies, birds and many more.

Cannibalism is most common among lower vertebrates and invertebrates often due to a predatory animal mistaking one of its own kinds for prey. But it also occurs among mammals and birds, mainly raptors and owls, especially when food is scarce”.

In birds of prey that use a larder or provisioning system of feeding young whereby there should be no food shortage, cannibalism has still been observed. There are several ideas as to why young owls or raptors eat their smaller siblings, or even where a parent eats part or the whole of a brood, but the theories are several and the explanations very detailed, too detailed to trouble most of us.

Will emailed me these photos he took while exploring a Little Owl nest to ring the young owlets. Because the nest cavity was deep and dark he couldn’t see into the hole, but found the young by touch, and also put his camera into the cavity and took a few pictures as a means of finding out where the birds hid.

The first picture below shows the remains of a Little Owl chick that was in the process of being eaten by a second chick. The second picture shows a third chick crouching in the corner of the hollow away from the incoming camera whilst the remains of the meal of Little Owl have moved around somewhat and a dead mouse serves as a later meal. The third picture shows the rather messy Little Owl that was probably caught in the act of eating the unfortunate victim sibling. The fourth picture shows the smaller bird that crouched in the corner!

Little Owl – corpse right centre

Little Owl - top left

Little Owl

Little Owl

Photographs by Will Price.


Birdringal-andalus said...

Stunning images!

Pete Woodruff said...

A most interesting post Phil, learning something every day and on this occasion with some revealing illustrations. I love it....excellent!

Mark Young said...

That's really fascinating Phil. I haven't heard of that before in birds.

Unravel said...

Never heard of this before as well...
Another proof that natural selection can be cruel.

Stu said...

Cute............................but evil.

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