Facts about Evolutionary Adaptations

 

Dyfi Osprey zygodactyl foot
 
Fact 11

Osprey legs (tarsi) are reticulate (scaly). Think of a goalkeeper that has padded gloves for better gripping of the ball – it is the same with ospreys and scaly legs to better hold on to its prey. Evolution got to the ball a lot quicker than Gordon Banks did.

Fact 12

Most raptors have toes which vary in size, ospreys don't. All four of its toes are the same length.

Fact 13

Most raptors have talons with grooves in them, running along their length. Ospreys don't - their talons are perfectly round.

Fact 14

Unlike any other raptor (excluding owls), ospreys can reverse their outer toe. Normally, they have three toes pointing forward and one back when perching. But when grabbing a slippery fish, they will hold it with two toes pointing forward, two back. This toe arrangement has a posh Latin name: Zygodactyly.

Fact 15

The osprey has large, scaly feet with sharp 'spicules' (little spines) beneath the talons for better grip of slippery fish.

Here's Glesni beautifully demonstrating her spicules..

Fact 16

All the bird of prey species in the UK have yellow legs and feet - apart from one which has white legs and feet. The osprey.

Fact 17

Ospreys have a specialised intestine with very strong enzymes to break down and absorb their fish meal - even the bones. Ospreys very rarely cough up undigested pellets like some other birds of prey do.

Fact 18

Ospreys have a strongly developed uropygial gland (oil gland). It is situated at the osprey's rump by the tail feathers and the osprey spreads the oil produced around its feathers by rubbing it and then preening. It has both a waterproofing function (handy for ospreys!) and an anti-parasitic function.

Fact 19

An osprey's nostril is long and slit-like which is unusual as most birds of prey have round nostrils. Osprey nostrils can be closed during underwater dives so that water doesn't enter the nasal cavities - a bit like nose-plugs in the swimming pool!

Fact 20

Ospreys have a clear eyelid called the nictitating membrane that they can draw over their eye when they enter the water to protect it - a bit like wearing swimming goggles.

Brenig demonstrates how an osprey's nictitating membrane works - 2015