Wednesday, 27 February 2013

Nest Box Checking, 2013

In 2011 FoCM obtained a Council grant which allowed us to put up 20 bird boxes on the Chorlton Ees and Ivy Green Local Nature Reserve (see John Agar’s blog entry for March 2011). We put up 10 boxes on the Ivy Green side of Chorlton Brook and 10 on the Chorlton Ees side.
Last year (15.01.2012) we checked to see if any of the boxes had been used over the previous nesting season, and to clean out those with old nests in. The results of this exercise are described in the blog post for 19.01.2013.

A couple of Sundays ago (17.02.2013) a group of us repeated the exercise. Again, it was John Agar’s son Mark who climbed the ladder and wielded the electric screwdriver to detach the boxes from their trees and then to re-attach them.
On the Ivy Green side of the brook all 10 boxes were still in place, but on the Chorlton Ees side only four of the original 10 were left (down from six the previous year).

Eight of the boxes we checked contained dry (-ish) nesting material and no eggs. We concluded that the occupiers of these nests had probably raised successful broods. Two boxes contained very damp material. This probably meant that these boxes had been penetrated by rain during the exceptionally wet summer of 2012; we couldn’t be certain if these soggy nests had contained successful broods (they could even have been abandoned part way through nest building). Three boxes contained un-hatched eggs and one contained a dead bird. Although the corpse was vey degraded, John thought that it was probably a Great Tit.
Most of the nests were, as we observed last year, constructed of moss on a foundation of dry grass. Nevertheless, a few contained fibres derived from human sources. Some contained bright red, wool-like fibres - which we couldn’t identify. There were also fluorescent, green-ish yellow fibres in some nests. FoCM member, Chris Hirst suddenly realised that these fibres came from tennis balls (!) Dog owners regularly take tennis balls into the area to throw for their pets to chase. The balls must, equally regularly, get lost and the nesting birds obviously see their bright, fibrous coverings as an ideal source of nesting material. I’m tempted to interpret the inclusion of these fibres as a form of avian interior decorating ... but mustn’t get carried away!

Even more bizarrely, a few of the damper boxes contained colonies of slugs. By coincidence a person from Inverness recently wrote to the Guardian about slugs in nest boxes; she wrote:
“Last autumn I took down the wooden bird houses from the silver birch and one of them when I opened it had at least 36 large slugs packed very, very tightly together in the box ... stuffed in. They appeared to be possibly hibernating although it was still early autumn and not cold. Actually looking at them it was rather like opening a tin of pilchards and seeing them all packed neatly and tightly together. I was so revolted that I could only rush to dispose of them and didn't even check whether they were alive or dead.”
None of our boxes contained that many slugs!

The above quote was contained in article by the Guardian correspondent, Jane Perrone (http://www.guardian.co.uk/lifeandstyle/gardening-blog/2013/feb/20/slugs) and contains some surprising information, namely that the slugs in the box were, almost certainly a “non-social aggregation” and probably represented a strategy to conserve moisture (do slugs ever ‘aggregate socially, I wonder? Getting carried away again! Sorry!). Also a group of slugs is called a “cornucopia”. Who knows? Perhaps you’ll get an opportunity to use that fact in a social situation!
I think I’d better stop now ...

Dave Bishop (27.02.2013)