Nest boxes and winter feeding, by Noah Walker

Two years ago I started what I thought would be a relatively small nest box project restricted to a small wood near where I live. However over the past two years, more and more boxes have been going up, more land has been covered and more feeding has begun. Now I have around 200 nest boxes of varying types spread over 8, soon to be 9 sites (3 woodland and 5 farmland). As I said in my last post in 2016 most of the nest boxes are targeted at woodland birds such as Blue Tits, Great Tits, Coal Tits and Nuthatches. Now though I’m trying to focus on Tree Sparrows around the Thames Valley. Tree Sparrows declined by 96% in England between 1967 and 2014 and are a rare sight in most areas.

This graph from the Breeding Bird Survey shows how much Tree Sparrows have declined in England.

Recently the project took a big step forward with support from the RSPB and a number of local farmers who were keen to help their farmland birds. Currently we are working with 8 farms trying to aid the recovery of typical farmland bird species through feeding. At 5 of these farms we are specifically aiding the return of Tree Sparrows by putting up nest boxes and feeding intensively. At this time of year I move from checking and monitoring nest boxes to maintenance and bird feeding.

Tree Sparrows, photo by John Harding

This winter I will also be making 20 more boxes for a new farm that has great potential for Tree Sparrows. Unfortunately Tree Sparrows won’t use the boxes until the second year of them being up so its especially important they go up as soon as possible to maximise the chance of them being used. Occasionally I have to empty out the nest box of the old nest. Usually I don’t do this as Tree Sparrows will reuse the old nest material and just refurbish the nest. Instead I only clean the boxes that have become full of Earwigs and faeces or contain dead chicks engulfed by the nest material from the previous year. At a few of the farms I have put up Little Owl boxes and a Barn Owl box so over the winter I will be checking the Little Owl boxes for signs of roosting individuals.

Hopefully one day soon Little Owls will nest in one of my boxes! This beautiful clutch was photographed by Graham Giddens.

Within the Tree Sparrow project the nest boxes provide a good nest site that Tree sparrows would otherwise struggle to find. This should help the productivity (breeding success) of the bird improve but then the young still have to make it through the rest of the summer and the following winter. To help the juvenile survival rates improve I will start feeding at all 8 of the farms within the next few weeks. At 5 of them I have been feeding since July because this should stop juveniles dying in the first few weeks of fledging and build the juvenile Tree Sparrow flocks up. Putting feeders out during the summer also means any ‘pioneer’ juveniles (dispersing from further away sites) will lock onto the food and further build the population. Other species that benefit from the feeding are Yellowhammers, Corn buntings, Reed Buntings, Linnets and Chaffinches in particular. To get the best idea of the strength of the populations of different species we ring at the sites during the winter. This gives us data on the movement, size and health of the population and any birds ringed as young in nest boxes could be re-caught and add evidence of juvenile survival.

A couple of my feeders

In the woodland site I will be putting up some nest boxes for Tawny Owls and Kestrels. Although too late for Tawny owls breeding next year it should give them time to investigate it and hopefully use it the following year. The rest of the small (passerine) nest boxes will be checked for any damage. Typically the nest boxes in woodland need cleaning out more often. This is usually because the species using them have more juvenile deaths and being on trees as opposed to posts they seem to get more bugs in.

I hope this post gives you some ideas for things you might do over the winter months.

Noah Walker, @NoahWal01