Monday, February 25, 2013

An evening with Gulls and Terns



Heuglin's Gulls

     Heuglin's Gull or Siberian Gull (Larus heuglini) is a seabird in the genus Larus. It is closely related to the Lesser Black-backed Gull (Larus fuscus) and is often classified as asubspecies of it. It has also been included within the Herring Gull (Larus argentatus).Birds in the eastern part of Heuglin's Gull's range are often paler grey above and are frequently considered to be a separate subspecies Larus heuglini taimyrensis (Taimyr Gull). Another possibility is that they are a result of hybridization between Heuglin's Gulls and Vega Gulls.Heuglin's Gulls breed in the tundra of northern Russia from the Kola Peninsula east to the Taymyr Peninsula
     


     They are regularly reported from Finland and may breed there. They migrate south to winter in SouthwestSouthEast Asia, and East Africa. Small numbers are seen in Southeast Asia, it has been recorded in South Africa and it may occur as a vagrant inWestern Europe.They are large gulls with a rounded head, strong bill and long legs and wings. Length is from 53 to 70 cm (21 to 28 in), wingspan is from 138 to 158 cm (54 to 62 in) and body mass is from 745 to 1,360 g (1.64 to 3.0 lb). Among standard measurements, the wing chord is 40.5 to 46.9 cm (15.9 to 18.5 in), the bill is 4.5 to 6.5 cm (1.8 to 2.6 in) and the tarsus is 5.9 to 7.8 cm (2.3 to 3.1 in). The back and wings are dark grey, variable in shade but often similar to the graelsii race of the slightly smaller Lesser Black-backed Gull
     




     In winter the head is only lightly streaked with brown but there is heavier streaking on the hindneck. The legs are usually yellow but can be pink.Moulting takes place later than in most of their relatives so birds still have unstreaked heads and worn primaries in September and October. The primary feathers may not be fully grown until February or March when the head is still streaked.They feed mainly on molluscsworms, and crustaceans.

Brown headed Gulls

    
 The Brown-headed GullChroicocephalus brunnicephalus, is a small gull which breeds in the high plateaus of central Asia from Turkmenistan to Mongolia. It is migratory, wintering on the coasts and large inland lakes of tropical southern Asia. As is the case with many gulls, it has traditionally been placed in the genus Larus.This gull breeds in colonies in large reedbeds or marshes, or on islands in lakes, nesting on the ground. Like most gulls, it is highly gregarious in winter, both when feeding or in evening roosts. It is not a pelagic species, and is rarely seen at sea far from coasts.This is a bold and opportunist feeder, which will scavenge in towns or take invertebrates in ploughed fields with equal relish.



     The Brown-headed Gull is slightly larger than Black-headed Gull. The summer adult has a pale brown head, lighter than that of Black-headed, a pale grey body, and red bill and legs. The black tips to the primary wing feathers have conspicuous white "mirrors". The underwing is grey with black flight feathers. The brown hood is lost in winter, leaving just dark vertical streaks.This bird takes two years to reach maturity. First year birds have a black terminal tail band, more dark areas in the wings, and, in summer, a less homogeneous hood.This is a noisy species, especially at colonies.

Black headed Gulls

     The Black-headed Gull (Chroicocephalus ridibundus) is a small gull which breeds in much of Europe and Asia, and also in coastal eastern Canada. Most of the population ismigratory, wintering further south, but some birds in the milder westernmost areas of Europe are resident. Some birds will also spend the winter in northeastern North America, where it was formerly known as the Common Black-headed Gull. As is the case with many gulls, it had previously been placed in the genus Larus.This gull is 38–44 cm (15-17½ in) long with a 94–105 cm (37–41 in) wingspan. In flight, the white leading edge to the wing is a good field mark. The summer adult has a chocolate-brown head (not black, although does look black from a distance), pale grey body, black tips to the primary wing feathers, and red bill and legs. The hood is lost in winter, leaving just 2 dark spots. It breeds in colonies in large reedbeds or marshes, or on islands in lakes, nesting on the ground. Like most gulls, it is highly gregarious in winter, both when feeding or in evening roosts. It is not a pelagic species and is rarely seen at sea far from coasts.The Black-headed Gull is a bold and opportunist feeder and will eat insects, fish, seeds, worms, scraps and carrion in towns, or take invertebrates in ploughed fields with equal relish. This is a noisy species, especially in colonies, with a familiar "kree-ar" call. Its scientific name means "laughing gull".



     This species takes two years to reach maturity. First-year birds have a black terminal tail band, more dark areas in the wings, and, in summer, a less fully developed dark hood. Like most gulls, Black-headed Gulls are long-lived birds, with a maximum age of at least 32.9 years recorded in the wild, in addition to an anecdote now regarded to be of dubious authenticity regarding a 63 year old bird.The eggs of the Black-headed Gull are considered a delicacy by some in the UK and are eaten hard boiled.In the 1990s, local Broome birder Brian Kane saw a strange species of bird while trawling the local sewer ponds. Upon seeing this bird, he called one of his many bird-watcher friends to verify the species, who confirmed that it was indeed a Black-headed Gull that Brian had stumbled across. This was the first recorded sighting of the species in Australia.

Caspian terns

     The Caspian Tern (Hydroprogne caspia, formerly Sterna caspia syn. Hydroprogne tschegravaHelopus caspius) is a species of tern, with a subcosmopolitan but scattered distribution. Despite its extensive range, it is monotypic of its genus, and has no subspecies accepted either.In New Zealand it is also known by the Maori name Taranui.It is the world's largest tern with a length of 48–60 cm (19–24 in), a wingspan of 127–145 cm (50–57 in) and a weight of 530–782 g (1.2-1.8 lb). Adult birds have black legs, and a long thick red-orange bill with a small black tip. They have a white head with a black cap and white neck, belly and tail. The upper wings and back are pale grey; the underwings are pale with dark primary feathers. In flight, the tail is less forked than other terns and wing tips black on the underside. In winter, the black cap is still present (unlike many other terns), but with some white streaking on the forehead. The call is a loud heron-like croak.


     Their breeding habitat is large lakes and ocean coasts in North America (including the Great Lakes), and locally in Europe (mainly around the Baltic Sea and Black Sea), AsiaAfrica, and Australasia (Australia and New Zealand). North American birds migrate to southern coasts, the West Indies and northernmost South America. European and Asian birds spend the non-breeding season in the Old World tropics. African and Australasian birds are resident or disperse over short distances.The global population is about 50,000 pairs; numbers in most regions are stable, but the Baltic Sea population (1,400–1,475 pairs in the early 1990s) is declining and of conservation concern.


     The Caspian Tern is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies.They feed mainly on fish, which they dive for, hovering high over the water and then plunging. They also occasionally eat large insects, the young and eggs of other birds and rodents. They may fly up to 60 km from the breeding colony to catch fish; it often fishes on freshwater lakes as well as at sea.Breeding is in spring and summer, with one to three pale blue green eggs, with heavy brown spotting, being laid. They nest either together in colonies, or singly in mixed colonies of other tern and gull species. The nest is on the ground among gravel and sand, or sometimes on vegetation; incubation lasts for 26–28 days. The chicks are variable in plumage pattern, from pale creamy to darker grey-brown; this variation assists adults in recognizing their own chicks when returning to the colony from feeding trips. Fledging occurs after 35–45 days.


   It was truely a huge flock of gulls and terns, whom we saw more than 100 in numbers and it was the perfect evening time that they find good food around the estuary. They were far off from where we were waiting for them. Suddenly to our surprise we saw a White Bellied Sea Eagle watching the gull-tern flock from high atop a tree nearby. The Sea eagle tried to dive into the flock of gull-terns and managed to catch a brown headed gull, which we could see only in Binoculars as they were quite far off from us. Sparked by the Sea Eagles dive, the whole flock flied across the sea to take around and they rightly came and landed in front of the place in the estuary where we were sitting and waiting for them. 


     The most amazing scene is the way they line-up and sit along the coast, estuary, in a well disciplined manner. But they were way more noisier than crows, while they were trying to land. 




     It was great sighting of gulls and terns for the beautiful Sunday's evening. I was joined by Mr.Deepak Sibal from Bangalore and Mr.RK Pai from Vittla for watching gulls and we could happily go home with the closer shots of gulls and terns like never before. Mr.Pai missed some closer shots as he had ventured too close to the gulls and they immediately got flushed away. It was a great birding indeed, though the gulls flushed away, as the lights were fading and it was demanding a higher ISO to compensate the low lights. But we chose to wind up for the day and it was the right time of the evening to do so. I missed my good friends Mr.Ajith Kamath & Mr.Ranganath Bhat in this spectacular sighting of terns and gulls, though I had asked them the morning for evening birding, but they couldn't make it for the evening.

     I was hand-holding a Canon EF 300mm F4L IS USM lens with a Tamron 1.4x extender, mounted on my Canon EOS 7D, which is a great combination, that helped me to get these many shots of the gulls. My burst mode was as usual on a full swing at 8 frames per second and every movement of the gulls-terns have been captured accurately. 
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