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Tuesday, 26 January 2016

The Watching Hour

Getting ready for the annual Big Garden Birdwatch this weekend Sat 30 - Sun 31 Jan.

I say 'getting ready', but a garden and a chair are all one needs, and even then the chair isn't essential. The study involves watching a garden (or other green space) for one hour and recording the birds you see, then sending these records to RSPB via the interweb link above. The scheme has run for over 36 years, with the value and statistical power to interpret results accumulating with each yearly repeat survey. This is very easy, rewarding fieldwork: you don't need to go anywhere near a field, plus can do it from an armchair with a cup of coffee. And still participate gathering nationally useful citizen science data, towards significant findings.

Image result for big garden birdwatch 2016

Over the last few years' Big Garden Birdwatching, it has mostly been house sparrows for me, but this is fine - good, in fact, that these seem to be surviving reasonably well in Exeter. Otherwise the house sparrow in the UK, traditionally ubiquitous, has declined overall 71% since 1977*, a proportion and rapidity enough for the species to crash on to the national Red List of birds of Conservation Concern.

Our tiny street-side city centre Exeter garden meanwhile, often hosts 10-15 at any one time. As sparrows live in colonial family groups, I'd assumed the same dozen or so individuals might be using several adjacent contiguous gardens, no doubt encouraged by birdfeeders and the safety of cover provided by a big old hedge. During 2015 hour's vigil, I counted 36 in the garden at the same time. A fleeting blue, great or coal tit was a source of moderate excitement. I suspect the collective sparrow gang does a good job of guarding and monopolising the feeder; ground feeding birds like dunnock, robin, and blackbirds put in a few more appearances, with a few more chances to pick up the feeder spillage jetsam underneath. There was a winter female blackcap once; crows, jackdaws and starlings are around but haven't come into the garden during the allotted hour; occasional pigeons and magpies usually add to the hour's species list.

Familiarity and local dominance doesn't preclude some sparrow subtleties to look out for. With the colder weather, fatballs seem to be preferred over seeds, grains or wholemeal bread, though the improvised bird baths are used just as much as usual, despite all the recent rain. As nesting season approaches, the black 'bib' patch on the male's chest becomes larger and glossier, indicating status among peers competing for mating opportunities. In breeding mode, the bill also darkens colour to shiny black from grey**. Such sparrow politics add interesting sub-plots to the garden observations.

Magnificent 7 sparrow posse
And results just in for my Garden Birdwatch hour, Sunday 31 January 2016:
Highest counts
Blackbird 2           House sparrow 16
Wood pigeon 2     Dunnock 1
Long-tailed tit 4    Wren 1

STOP PRESS: RSPB have now published the 2016 results - link here
There are downloadable spreadsheets to see county and national results. In Devon, there was an average of 4 house sparrows per site, present in 67.4% of participating gardens/open spaces. Most widespread species was blackbird, in 86.6% of gardens, followed by robin 84.5%. Some other interesting records were barn owl, redpoll and yellowhammer.

* from BTO and RSPB sparrow webpages. Various reasons have been suggested for the decline: a drop in survival rates of chicks; decline in invertebrate prey; concreting over of gardens; as yet no single cause is known
**as told by eminent sparrow expert Denis Summers-Smith, in Hugh Warwick's Beauty in the Beast book, and in a scientific paper from 2010.

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