Sunday, September 11, 2011

Going Away

Previously known as the Grey lourie, this is now called the Go-Away bird - and "similarly" I'll be going away = on tour again until end of the month.

Friday, September 9, 2011

Cainism amongst Eagles

Talking about eagles [SEE: previous blog entry] - some of these large raptors are prone to Cainism, also known as the Cain & Abel syndrome OR Siblicide, meaning that the older chick in a nest kills the younger within the first few days of hatching. So if you see a Black eagle circling, it has to be "a Cain"!

Like the Black eagle, a Tawny eagle chick also follows this pattern, as well as Crowned eagles, Augur buzzard chicks & sometimes, the older of 2 Jackal buzzard chicks may kill the younger, but not always.

So again, this Tawny eagle youngster can be called "Cain" - the oldest of 2 chicks, meaning that (usually) it hatched in a nest consisting of only 2 eggs. In theory, Cainism amongst large raptors is a taxonomically, avian phenomenon as a consequence of food stress. However it was observed that food supplements do not decrease sibling aggression.

Similarly it's being said that siblicide is also common amongst Ground hornbills, although I haven't "discovered" any proof of that. Instead it appears that only 1 egg in a Ground hornbill nest hatches!?

In contrast (or similar to the above) the clutch of a Martial eagle consists of only 1 egg - which is also the case amongst most of the other eagles that do not practise Canism.

A female Wahlberg eagle also tends to mostly lay only 1 egg, although it was observed that a small percentage of these clutches had 2 eggs.

The clutch of an (African) Fish eagle usually consists of 2 eggs, although both of these eagle youngsters do not always survive. Differently to most of the other eagle species, a male Fish eagle also "shares nest duties" with the female - the couple virtually take turns incubating the eggs.

However once 1 or 2 chicks hatched, the male Fish eagle only assists feeding small nestlings. After that a Fish eagle youngster is fed mostly by the female.

Friday, September 2, 2011

The Eagle Landed

A soaring Fish eagle is beautiful to behold & the experience is even more "magic" when this raptor calls out in flight - a sound typically associated with Africa.

Also called the African fish eagle, this bird tends to hunt from a perch, catching fish with its feet without checking its flight. Its prey/fish tend to weigh between 1 & 3kg.

Other than catching fish, this eagle also robs other fish-eating birds of their prey or raids other waterbirds of their young as well as their eggs. The African fish eagle is usually found in pairs.

Another magnificently soaring raptor is the Brown snake eagle - found mostly in the northern & eastern parts of our country, where it's status is mostly known as an uncommon resident.

The Brown snake eagle is usually solitary & tends to fly from one hunting perch to another. As its name indicates, this bird feeds mainly on snakes, which it kills & swallows whilst on the ground. As this photo "proves", this eagle is said to have an owl-like face.

In flight a Bateleur (eagle) is easy to identify by its mainly white underwings & up-swept wingtips, other than its characteristic, circling but seldom flapping, flight pattern, whilst it also looks almost tailless. This bird occurs mainly in the Lowveld part of our country, e.g. often soaring high in the Kruger National Park.

In contrast to other raptors, which are the most difficult birds to identify (especially when immature), an adult Bateleur can hardly be mistaken for another eagle, because it "sports" red legs/feet & a (mostly) red cere (= beak). Its food varies from insects, fish, reptiles, other birds, small mammals to carrion. It also tends to rob other eagles and vultures of food.