Yellow fellow

I took this photo from my Q garden of a Ring-necked Parakeet recently. Is a yellow variation very common and is this bird likely to be an escapee? Kevin Gower

A I don’t know where you live, Kevin, but we have had a single all-yellow Ring-necked Parakeet in the newly established population of parakeets in Peterborough, which spend a large amount of time at Ferry Meadows CP. The flock there is about 25-30 strong and one of the older adults, and presumed parent of many of the younger ones (including the yellow bird), is a blueish parakeet with coloured rings, which is a known escape. The presumption that this bird is the parent of the yellow bird (apart from the age difference and the fact that the blue bird has been seen at a nest) is based on our rudimentary thoughts about genetics. We are jumping to the conclusion that having had its colour genes ‘manipulated’ through selective breeding, the ‘ blue’ bird would pass on genes which could cause changes in the pigments of its offsprings’ feathers.

The northern part of the Peterborough area has an established naturalised breeding population of Red-crested Pochards, and there appears to be a disproportionate amount of birds with odd pigmentation (often pale birds) among these ducks. The limited amount of genes within this small population and subsequent ‘ in-breeding’ is believed to have influenced this.

Perhaps it is a similar story with your yellow parakeet (which are not that common, incidentally).

And a grouse in a Hawthorn tree

Q How common is it to find a Red Grouse at the top of Hawthorn tree eating berries? This one was, and finding it quite hard to move from branch to branch, which is perhaps understandable for a ground feeder. I would be pleased to get your answer.

Ken Ormonde, Kirkby Stephen, Cumbria

A This is a fascinating photograph, Ken, of a male grouse seemingly enjoying the haws on that Hawthorn. Most Red Grouse in the UK live on heather moorland, generally in areas well away from significant tree cover, so don’t tend to stray too far in search of food. Continental Willow Grouse (a subspecies of the same bird which turns white in winter) often live in more mixed habitats and are known to readily take berries, usually from dwarf trees ( bilberries and the like). In the UK, Red Grouse apparently usually only head into the trees in extreme conditions (eg deep freeze). Of course, other grouse are more at home in trees. In the UK, this means Black Grouse and particularly Capercaillies, which spend most of the winter in pine trees.

Bird flu in swans?

Q I live in north Cambridgeshire and have noticed what seems an unusually large amount of dead swans, recently. They appear to be well away from power lines, so collisions do not seem to be the cause. Is it possible they have some kind of disease, perhaps even Avian Influenza.

Rowan Wright

A Your query is pertinent, Rowan, as at the time of going to press (in December 2020) there is serious concern in the fenland of northern Cambridgeshire that the wild swan population could be suffering from an outbreak of Avian Influenza. Recent Wetland Bird Survey ( WeBS) counts have found more than 2,000 Whooper Swans in the area surrounding the Nene Washes (an area managed by the RSPB). And RSPB staff have noted high numbers of dead swans (more than 20), particularly Whoopers, in recent weeks. Currently, analysis is being carried out on samples from the dead swans on the reserve. If it is AI, it could have implications for local poultry owners (with potential culls) as well as decimating the swans etc in this vital wintering ground for wildlife.