Tuesday 7 April 2015

Dungeness with ducks, grebes and geese.

I was very pleased to see a female Goldeneye on the left viewing from the Dennis hide, and then delighted to see a small group flying across the front to the right in front of the old lighthouse, which I just managed to catch with the Sigma lens.


I talked a bit about the male displays and the overall lifestyle in another blog, Goldeneye at Cliffe Pools.

It was really nice to see the Great Crested Grebes fairly close in to the front of the hide:


There were good numbers of Northern Shovellers, Anas clypeata, all across the Burrowes Pit. In this individual the whitish channel of feathers between the chestnut ones above the leg can be seen. I have looked for it online, and detected it in a number of other examples, where the thighs are thrust forward. However I have to say that I don't understand exactly what is going on here. Could it be the down feathers beneath?


A closer view:


A view of the white channels from the rear! You can also see the tail pattern of the central dark area with the surrounding white feathers to the side of the tail.


There are four species of Shoveller ducks in the World, the Northern, Anas clypeata, that we are familiar, the Cape, Anas smithii, from (mainly) Southern Africa, the Australasian, Anas rhynchotis, from Australasia (!), and the Red, Anas platalea, from South America. They are all in the genus Anas, and I assume that they all have a common origin - perhaps!

The shape of the bill is to do with the feeding diet. The bill is used to filter tiny animals such as Cladocerans, such as Daphnia, and Ostracods out of the water. This is a very specialised diet, and one of the major problems is that Cladoceran populations crash in mid-summer, leading to significant weight loss over the summer in the Shoveller males, and even apparently death in the females, and perhaps the young, despite their attempts to turn to alternative sources of food. The males cope at least in part by really great efforts to build up reserves by intensive foraging earlier in the year, and then minimising their foraging when their diet is scarce, apparently remaining in hiding, somewhat unseen.

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