Thursday, 19 April 2012

Cooler Weather in the Middle of April

Singing Nightingale out in the open

Wren belting out it's incredible song
A very striking male Marsh Harrier is still hanging around Barbate Marismas. I haven't seen any female but looking at his plumage he looks as if he'd be a fine suitor for any female. The birds are certainly singing but what's happening? Well, more thoughts on this below...
Swallowtail Butterfly are slow to come through this season and like many birds aren't moving away
Swallowtail Butterfly in flight
A Montagu's Harrier adult male passing through La Janda. There's still lots of raptor activity on The Strait although the weather has been so mixed that we've not been seeing the often impressive sights of hundreds of birds crossing - apart from Black Kites that is. There has been a lot of higher altitude migration and later than normal passage. I suppose these cold winds from the north and the more unsettled and extremely changeable weather throughout Europe has had an effect. Logically you don't want to be in any country when there's still snow falling! There was a report this morning of new snowfalls on the Sierra de Gredos, north of Monfrague in Extremadura. I'm off to Trujillo on Saturday for four nights then down to the Coto Doñana for three leading a Limosa Holidays Group tour. I'd better take an extra fleece for the Extramaduran part of the tour...

A Booted Eagle on the coast at Guadalmesi. We've seen a lot of birds cross then just hang around the area of The Strait and not really in a hurry to get on with travelling further to their breeding grounds. Similarly slow passage of a lot of warblers will mean late birds in the UK and other European countries. Birds too have a fascinating ability to read weather and certainly know when to stay put. Their biological clocks are ticking and many birds time breeding with that of other living creatures. Insects, small mammals and passerines make up the diet of breeding raptors like this Booted Eagle and the Montagu's Harrier. 
Last year we were remarking about how early the seasons are starting, particularly with early springs, now there seems to be an abrupt halt to this trend. In any case the whole world is seeing huge changes in climate and many unnatural and prolonged weather patterns, with intense flooding in Australia, violent hurricanes across the Caribbean, Mexico and the US, unseasonably high spring temperatures in the UK, tornadoes in the Midwestern US and drought in many European countries.
Booted Eagle darker/intermediate form
Booted Eagle in flight. You can just make out one of his 'landing lights' or white shoulder patches
Booted Eagle - the more common lighter coloured form
Booted Eagle lighter form from above
Takeoff! This intermediate form shows his 'boot's really well and the amount of moult and obvious replacement on various sections of the under wing
Short-toed Eagle
... watching and turning

White-headed Duck

(Oxyura leucocephala)

  male in breeding plumage

We had a few days over on the Guadalquivir recently with some lovely people. I always enjoy showing and talking about the history, physical layout and wildlife delights of this vast flatland with the wide Guadalquivir River cutting through both sides of  what are now the Doñana parks system. White-headed Ducks are still scarce breeding birds in Europe and usually we can see them at several small freshwater lagunas or lakes in and around the Algaida and Bonanza area.
 A few people have asked me recently about the unusual colouration on the bill of the male White-headed Ducks, especially during the breeding season when it almost looks like a cartoon drawing or something from a caricature
A week or so ago, I wrote something about iridescent plumage of birds and tried to explain what physically caused it and the reasons for such, when you'd think that birds wouldn't wish to attract attention to themselves with so many predators around.
I think that the colour phenomenon of this particular species of duck is very similar to that in those wonderful iridescent feathers of birds such as the Northern Bald and of course Glossy Ibises.
The underlying feature of the blue bill seems to show that the colour is a consequence the reflection of blue wavelengths by a colourless superficial layer with absorption of all other wave-lengths of incident light by a deeper black layer containing large amounts of melanin. Some studies have been done on Ruddy Ducks, a very similar 'stifftail' species and show that the blue bill colour is a physical, structural phenomenon and not due to the accumulation of a specific blue pigment.
White-headed Ducks make a lovely soft whistling call mixed with some clicking sounds.Their displays involve tail-flattening on the water, wing spreading and as a lot of ducks and other water birds do, some stretching and standing high in the water.
These birds are known collectively as 'stifftails' and that exactly the position they adopt to display. They also use it as a warning to other birds, raising it high and as in mating flattening it on the surface of the water, lowering and elongating the neck and head and body and paddling flat out in the direction of the female or for that matter another male.

Slender-billed Gull

 (Larus genei).

 Slender-billed Gull have to be one of the most lovely looking Gulls we have along with the Audouin's Gull. This particular bird has lost his left leg and seems to be managing fine without it. You can see that lovely pink hue as it comes into adult breeding plumage. The pink colour may be attributed to diet as with flamingos, their diet contains a high percentage of tiny shrimps that breed in the saline waters of the salt-pans.
 Slender-billed Gulls hunt and just like Audouin's aren't scavengers. They are fast and opportunistic like a lot of gulls but do spend a lot of time picking at shrimp larvae, often in the company of Black-headed Gulls which are about the same size.

You can see that lovely pink of the breast and red eye. The slim, longer neck and head shape tell you that it's different and the bill is quite slender.

Wing colour and shape are also similar to Black-headed but again the structure of the neck, head and bill show differences. In winter Black-headed Gulls lose their dark hood but they do retain quite prominent ear spots of dark grey or black. The Slender-billed has tiny faint ear spots but as I say the structure of the bird would tell you the difference between the two.

Some wing action
Long-winged and quite beautiful

Marbled Teal (Marmaronetta angustirostris

One of the rarest European Ducks. Most of the population is in Cadiz province and there are some increases in Huelva and Malaga provinces within Andalucía. I'm not sure of the Portuguese status.

Black-crowned Night Heron

Black-winged Stilts

Lovely birds although slightly neurotic....

Butterfly effect!

Flight of European Spoonbills on spring migration

Great Egret

Horse in Wild Mustard

Breeding plumage of a male Little Ringed Plover

A Pied Avocet dances across the water

Almost invisible, the wonderfully camouflaged Purple Swamphen

Whiskered Tern

Gull-billed Terns show a slower flight with deeper beats. They have a big head and neck and the bill is chunky and points straight ahead. The Whiskered Tern is a dainty flier, more bouncy and faster beats with it's silhouette showing a more angular bill and smaller head
Zitting Cisticola (Spitting pepsicola)

Friday, 13 April 2012

Cream-coloured Courser at Tarifa - 12th April 2012

One of the rarest waders to turn up in Europe was found by a teacher with a party of schoolchildren out on a field trip on Tarifa beach on the morning of the 12th of April 2012. The teacher knew that it was an unusual bird and phoned Fundación Migres, a local NGO that studies bird migration on The Strait of Gibraltar and described the bird to them. A search was made and the bird was re-located a short distance from the original location. I heard about the sighting around midday but unfortunately I was with French clients over on the other side of the county at the Guadalquivir River.

It's last position was here: 36° 1'31.61"N 5°37'2.35"W

Later that evening I travelled down to Tarifa and made a search, finally locating this wonderful bird. These are some of the photos I managed to take just as the sun was going down behind a stormy sky.

Fortunately it didn't rain and I managed to get some photos in good light

They are generally quite confiding birds and blend in really well against a sandy background. It's normally their running around that gives them away

The courser's view as it settled down for the night on The Strait