Focus on Oystercatchers and godwits

Friday, 11 September 2009

High tide 16.08 (4.2m) Low tide 09.14 (1.5m)

F5 NE breeze, cool, sunny, a typical autumn day…

The weather has turned cooler and distinctly autumnal for the last three days with an increasing north-easterly breeze. The area of high pressure causing this air flow has yet to reach Scandinavia so the hoped-for migrants (including rarities) from the east have yet to start arriving in southern Britain, never mind Hampshire! Farlington is clearly the place to be regardless of the bird forecast so I dutifully spent a good few hours wandering around from mid-morning.

The bushes area held the expected selection of commoner silvia warblers including a couple each of Lesser Whitethroat and Common Whitethroat amongst the Blackcaps, plus two Chiffchaffs. A Sparrowhawk put a flock of 20 Meadow Pipits up from the ground beside the main lake as well as three Common Snipe. Like yesterday a small passage of swallows and martins was taking place overhead so I positoned myself along the main path through the bushes area to get a good view across the reserve. Groups of House Martins were arriving from the west and stopping very briefly to drink in the fresh water along the stream before continuing eastwards. Smaller numbers of Swallows and a few Sand Martins were also mixed in with them. This passage continued for about an hour but soon died away and thereafter a thin trickle of mostly Swallows was noted throughout the rest of the day.

Small birds, especially migrants, often gather to feed in the same areas in the more sheltered parts of the reserve to feed when it’s windy. Today was no exception and a collection of such birds, probably all newly arrived, was to be found in the field edge in the lea of the north-east seawall. A single Redstart was probably the best, followed by three Whinchats. There was also a Garden Warbler, a Common Whitethroat and two each of Lesser Whitethroat and Sedge Warbler.

It was now almost afternoon so I toured the seawall in my usual clockwise pattern. The Deeps provided no new birds at all, although the family of Oystercatchers that I had seen there previously were feeding on the parched grassland looking for invertebrates to eat. The family comprised two adults and a juvenile. As is typical for this species the juvenile, althogh fully fledged, was still heavily reliant on the parents for food. Locally raised young birds learn foraging and feeding skills from their elders. The parents were typically attentive, and while I was watching it was the male that was being shadowed by the learner. I could still hear the high-pitched chick-like contact / begging calls given by it. Finding invertebrates in the grass or top soil at this time of year has possibly been made more difficult by the continuing dry conditions. Finding worms in the harbour mud would probably be much easier and is what many young Oystercatchers do. They do also feed on shellfish, mostly cockles and mussels (rather than oysters) but the skills required to break into the hard shells to extract the animal inside is one learned slowly. Below is a short video clip of the juvenile feeding with one of the adults at Farlington:

The dry weather (we have barely had any rain since July) has resulted in the Deeps being less than its namesake. It is currently a very shallow pool that has mostly dried up. The Little Grebes on it have only just about enough depth to dive into. Mostly they “snorkel” in search of food – head down into the water peering into the murky shallows in much the same position as the two juvenile Shelducks use to feed (although they are sifting the water for much smaller animals). Today two Little Egrets are also wading about with one seen to take a small fish (probably a stickleback).

The main Langstone Harbour islands, Baker’s and South Binness, have a Peregrine each, including the dark adult male that I have noted recently.

The two juvenile Ruff, first seen on 6th, are still on the lake, along with two Avocets, 14 Greenshanks, six Knot and 130 Grey Plovers amongst the usual species.Todays total of 442 Black-tailed Godwits was the highest I have seen on the reserve this year so far and included 17 juveniles. There were also at least 31 different colour-ringed birds in the flock including a bird that was marked as a chick in Iceland in 1999 during one of the first annual summer trips to that country by representatives of the Farlington Ringing Group. You can learn more about this long-running scheme, which is international in organisation and participation, and now called Operation Godwit, from the following video by Jim Wilson:

In short, each bird caught is marked with a unique combination of coloured rings which then enable anyone, with a good view and through optics, to record it where ever it goes. Many of the birds have long and fascinating life histories which have contributed to building a useful database of re-sightings. We now know much more about this species then when the scheme started in 1991, everything from population size, migration routes and survival strategies, to wintering distribution and longevity.