Wednesday, 23 May 2012

Eider Island

 It’s not often I get to go ringing in Scotland so when I received an email asking for help ringing a nationally important colony of Eider ducks off the West coast, I jumped at the chance.

I had never ringed Eider ducks before and so was very much looking forward to joining the Clyde Ringing Group on their annual expedition to Horse Island, targeting the species as part of a BTO RAS project (Retrapping Adults for Survival). More information on RAS can be found here.

Horse Island
We were blessed with a rare hot sunny day complete with calm, flat seas which made for a smooth crossing to the island which lays just off Ardrossan. As we left the harbour and set sail for the island we were greeted by Black Guillemots and the distant OooooO calls from the Eiders.

The aim of the day was to catch as many of the female Eiders on thier nests as possible. They were caught using landing nets and the small team of catchers worked together and moved around the island in a group in order to avoid causing too much disturbance to the nests birds.

Looking for the next target

An Eider caught at her nest ready for ringing.
A number of biometrics were taken from the Eiders and their eggs were also aged using a technique of placing an egg in a small bucket of water. The height at which the egg floats then tells you how far into incubation it is, from this you can then work out a laying date as well as an expected hatching date for the clutch.

Ageing Eider eggs

I was surprised to learn how skinny the females were after having spent the last month sat tight on their eggs, not being able to feed.

Being weighed (Eider in a bag!)

I always enjoy being in a seabird colony, the atmosphere, the adults calling overhead and yes even the smell, weird I know! As well as seeing my first Eider nest I also enjoyed seeing so many different gull nests as all three Lesser Black-backed, Greater Black-backed and Herring gulls nest on the island.

Resourceful nesting at its' best!

Spot the nest!
Variation in gull eggs

Hatching gull chick

Eider nest
I was rather surprised at the amount of egg dumping that was taking place. Many Eider nests contained Mallard and even gull eggs but it wasn’t only other species that were dumping as one poor Eider was sitting on 9 eggs (an average clutch size for the island being only 5).

This Eiders going to have her hands full!

Spot the odd one out

It was also a real treat to see my first Eider chicks, many of which were hatching out of their eggs as we found them.

Hatching Eider

Newly hatched Eider chick
As well as Eider chicks, there was also a good number of gull chicks about too including this Great Black-back. 
Over 80 new adult Eiders were caught during the day with many more already ringed birds being processed too.

Everyone had a throughally enjoyable day on the island – we even had fantastic views of a Peregrine as we sat down for lunch surrounded by nesting gulls who were evidently eyeing up our lunches!

"You going to finish that sandwich?"
It was a great experience and I learned a lot. It was really useful for my training to get to grips with using the larger sized rings and playing the role of a ‘catcher’ was great fun too – even managed to catch a couple of Eiders by hand. I must say that after hearing so many warning stories of the horrors of Eider poo, I really didn’t find it that bad – I’m yet to find something that smells worse that Coot poo! I also managed not to get pooed on once by the dive bombing gulls overhead – no idea how I did that!

My first Eider - especially loved the way she made soft Oooo sounds in my hands, beautiful birds.
I want to say a massive thanks to The Clyde Ringing Group who are always so welcoming to me and especially to Iain for inviting me along.

1 comment:

  1. Fascinating stuff - and great photos! It looks like you had quite the experience. Thanks again for sharing it.