Bird-ringing this morning, so I headed off just before 6.00 a.m. to Le Chateau des Marais. My trainer, Trevor Bourgaize has been working hard over the autumn and winter to create rides for netting. Mist nets have a fine mesh and are set vertically. It takes a long time and lots of patience to develop the skills to take a bird out of the net and place it into a cotton bag. This helps to calm the bird and keep it secure before taking it back to the ringing area. The bird’s species is recorded. It is then ringed and where possible its age and sex is determined. We then measure its wing length and weight before releasing it unharmed.
The weather this spring has been cold with north-easterly winds, so migrants have been thin on the ground so far. The first bird today was a Willow Warbler, seen in the top photo. We also had Chiffchaff and the photos show how hard it can be to tell these two species apart, unless they happen to be singing. Willow Warblers have longer wings and a knowledge of small differences in plumage helps to confirm the ID. These two species have migrated from Africa and the Mediterranean, which is nothing short of miraculous for birds that weigh around 10g.
To listen to the Willow Warbler’s flutey, descending song, and the Chiffchaff’s simpler song which heralds spring, examples can be found on the excellent website: https://www.xeno-canto.org
In recent years, milder winters have encouraged some Chiffchaffs to stay in the Bailiwick and southern areas of the UK. It’s a risky strategy that pays off if the weather stays mild and there are insects around for them to feed on, They avoid a long, hazardous flight. However, they would struggle to survive through a prolonged period of cold weather.
Both Willow Warbler and Chiffchaff feed on insects in woodland and scrub where there is plenty of cover. While some Chiffchaff stay to breed, the Willow Warbler will continue to migrate up to northern England and Scotland.
Natural history of the Bailiwick of Guernsey 