Springwatch 2011. Feeding garden birds study.

[astarsdad]

A couple of days ago there was an item regarding feeding garden birds on Springwatch. A university had conducted a study to see if birds have benefitted from having food provided for them in the way of feeders etc. Their early conclusions suggest that it may be harmful to birds if you are also providing nest boxes during the breeding season. Their study argued that because of territorial issues, the nesting birds time was taken away from providing for their young. Their findings were that clutches and surviving young were lower in this habitat.
Their recommendations were that it is best to keep nest boxes as far away from feeders as possible. It made sense to me.
I wonder if it would be possible for the RSPB to study this problem themselves and provide some guidelines?

[~T~]

It does make sense, so if you have nesting birds don't feed (unless you have a very large garden) and if you don't then do feed.

I must hold my hands up and say I've gone against this and continued to feed in my very small garden even though I have a nesting pair of blue tits. My main reasons for this is I had thought they actually had decided not to nest after initially showing interest in the box as I didn't see the adults for ages then they didn't seem to bother with any other birds in the garden excluding corvids. Even then they just wait for the corvids to leave (which is only a few minutes at most) before continuing their chick feeding. Now that the chicks are nearing fledging I've cut food down to just a seed feeder and really only get sparrows and other smaller birds so hopefully the chicks will fledge safely (that's if the resident cats don't notice).

[2dogs2000]

I feed the birds and don't have any nest boxes in my small garden. A pair of blue tits chose to nest in an air brick in my house. Does this mean I should have stopped feeding the birds? They managed to rear their young and they fledged successfully.

[k4t3]

I feed the birds in my garden, but have never provided nest boxes. I get many fledglings in the garden in spring though, crowded round the feeding stations, begging for the adults to feed them...please tell me I am not doing wrong?!

[camo]

There are no hard and fast rules. I have at least 5 different bird species successfully nesting within twenty feet of our large feeding station. Of these the Blue Tits and House sparrows are in boxes but the others are all natural nests. In each case the birds chose to site their nests close to the station. In addition we had a further three species of fledgling being fed in the garden.

The logic of smaller brood sizes due to tinme lost on defending a nest is sound but a good feeding station will sustain many more nests than it will harm.

A bird will make a nest choice by balancing the pros and cons with a ready made box and an easy feed with the extra work involved in building and commuting. The other benefit of boxes is a warm shelter in the winter which should not be ignored.

Roy

[King Edward]

Since birds will travel quite a distance to a feeder, I'd have thought that the large number of pairs benefitting from the food would outweigh any disadvantage to the small number of nests in the immediate vicinity of the feeders. I suppose it does make sense not to put boxes up right next to feeders - is there any minimum recommended distance, or just 'as far as possible'?

[Elizabeth B]

We have 6 hanging feeders in the back garden, also a bird table and I scatter food on the lawn for the ground feeding birds. The garden is about 55' square.

We have three nest boxes, one in the small front garden, one at the side and one at the bottom which is about 18' from one of the feeder poles. The boxes are usually quite successful but this year was our best ever - a total of 26 chicks fledging from the three boxes. (10, 9 and 7).

However, I think our garden is not a typical suburban garden, as there is a row of mature trees down one side, with several different species including two oak trees. The other boundaries have a few trees and tall thick hedges. There are also mature trees in neighbouring gardens - all these probably provide a suitable habitat for grubs, caterpillars etc.

[RKB]

I thought it was a bit pointless to ask a birdfood producer (the farmer) and birdfood retailers (RSPB and BTO) if we should keep feeding birds. They all have a vested interest in the answer. Some independent voices would have been useful.

I am also very wary of the conclusion - that territorial issues were the big problem. Birds (especially tits, which the study was about) are not actually very territorial when they are feeding young, as they don't have to be - the territory has already done its job. They are most territorial of 'land' before nest-building (to space themselves out), and then very territorial of the female while she's fertile/laying (to stop others fertilising her), but the latter only involves a fraction of the land area of the former. Several studies show this. Once they have chicks, they're not really defending their territory at all. Think of when you hear Great Tits singing - before they have a nest or while they have young?

So the idea that birds get stressed by having to drive away others from their nest doesn't really stack up very well. Also, it is the male that defends territory but the female that controls brood size - so how can territory defence influence the brood size if the bird doing the defending isn't the one that decides how many eggs to lay?

What feeding does do is bring forward egg laying, by bringing the female into breeding condition earlier due to extra nutrition. But that can mean that she becomes out of sync with the food that she feeds to the chicks - i.e. caterpillars. Without artificial feeding, the adults eat the caterpillars and the increasing population of bugs will tell them when to start laying. But if the adults are loaded up with sunflower seeds then they are not 'following' the caterpillars closely. So they can lay (and hatch young) before enough caterpillars are out. The birds are then out of kilter with the chick food, and chicks can go hungry (as they can't thrive on the birdfood like the adults can). There are plenty of studies on tits and the caterpillar peak, showing how finely-balanced it is (which is why tits all tend to nest at the same time).