Tuesday, 15 December 2015

Photographic Advent Calendar, Day 14: Oystercatcher

This has to be one of those birds that truly epitomises the coast: no stretch of shoreline is complete without at least a few pairs of feisty Oystercatchers dive-bombing intruders and issuing their piercing calls with persistent vigour. Although they can get a little vexing after a whole spring of harassment, they really are smart birds. We have around 60 pairs here on Bardsey, with a wintering population of between 60 and 100. Across the UK, there are around 110, 000 breeding pairs; despite this, recent population declines have placed it on the amber list, and it is listed more widely on the European red list.

Anyway, onto the birds themselves...they have some rather cool adaptations to suit their lifestyle of feeding on bivalve molluscs such as mussels and cockles. The species can deploy one of two techniques for tackling these tricky meals, and these techniques are passed from parent to offspring. The first technique involves hammering through the side of the shell, creating a hole through which they can extract the organism within; the second relies on the use of the flat bill to prize open the two sides of the bivalve, before severing the adductor muscles and taking the reward. These fascinating aspects of behaviour have also influenced the morphology of the birds, encouraging shorter, stouter bills with the 'hammering' technique, and longer, thinner bills with the 'stabbing' one. Due to this specialised form of feeding, juvenile birds have been observed associating with their parents up to a year after hatching!

One more cool fact...the scientific name for this species (Haemotopus ostralegus) can be translated roughly to 'blood-foot' (haima + pous) and 'to lift oysters' (ostrea is an oyster, and legere is 'to lift'). Very descriptive! They also used to go by the old name of 'sea pie'.

If you would like to see more of my Oystercatcher images, you can check out the gallery on my website here

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