Cambridgeshire Bird Club

Cambridgeshire Spotted Flycatcher Project  2018

The Club is planning to continue the survey of breeding Spotted Flycatchers into 2018

Report on the 2016 season: the challenges of Spofling

2016 was the second year of this survey and we found many more pairs than we had in 2015, mainly because we put in more effort and hours. A hundred or so observers sent in records. A high proportion of these turned out not to be Club members but ordinary householders (often still BTO and RSPB members) responding to publicity in parish magazines and on websites. Genuine citizen science!

Most pairs were finally pinned down by dogged fieldwork from a handful of flycatcher aficionados, cold-searching traditional sites, peering suspiciously into people's gardens and lurking in churchyards. Most popular were gardens (not necessarily large ones) with good herbaceous plantings and often with some water (free-range dogs seemed to help too, deterring cats, squirrels and corvids); and parkland or churchyards with good nettle or umbellifer patches, often under pollarded limes or with animals. None was in our cities, and none was in or directly adjacent to arable farmed land. Pairs were generally unobtrusive and often entirely silent. Many never ranged further than 50 or so metres from their nest-site; others only fed high in the canopy. Quite a nesting challenge!

We confirmed 58 pairs as definitely breeding, at 49 sites (there were some mini-'colonies'). We found 36 actual nests, and most of the other confirmed records were based on reports of adults with very recently fledged noisy dependent young either close by where birds had been present earlier through the season, or at traditional sites from previous years but where we couldn't find the actual nest this year.

There were a further nine probable/almost certain pairs - one or two birds present on several occasions in good habitat or again at traditional sites. Some of these may have failed, or been predated, or may just have been single unrequited birds. And we had a further 19 possible pairs at new or non-traditional sites; but again, many may just have been single unpaired birds.

This makes a maximum total of 86 pairs, which I suspect (wild guess) represents 20 to 60% of the likely Cambridgeshire total. This is nicely in line with the 2007-11 Cambridgeshire Bird Atlas ‘guesstimate of 100 to 200 pairs in the County.

Flycatchers continue to be in deep decline.

This year I had the opportunity of working with the BTO's Chris Hewson and Lee Barber on a geolocator project, divided between Cambridgeshire and Devon.

SpotFly problems are as likely to be during the nine months they are out of the UK as they are here. There are only half-a-dozen ring-recoveries ever south of the Sahara, so we don't really know where they go or what threats they might be facing. Cutting-edge geolocators for birds of this size now weigh about 0.3 gms - that's a tiny fraction of a flycatcher's body weight, or a grain of rice. But this constraint means that there can be no antenna, solar-recharging or remote satellite sensing (as you can with Cuckoos and Nightjars). The geolocators need to be retrieved at some stage to be read. All they do is record light change and time, so that by recording dawn, dusk and time you have a rough idea of where the bird is every day.

Keen eyesight, virtuoso manoeuvrability and near-zero braking distances made the birds tricky to mist-net, but they turned out to be suckers for perch-traps! We fell just one short of our funded quota of twenty tagged birds (plus another twenty 'controls' for comparisons of survival) and all we have to do now is recapture them this summer to retrieve the devices and download the data. Some 66 nestlings were ringed, mainly by the BTO's Lee Barber. Some pairs were leading interesting lives: one menage-a-trois saw a single male bird with two females and nests on the go on opposite sides of the same house. And there were two cases of males apparently abandoning single mums as soon as nest-provisioning duties were required. This sort of bad behaviour is only revealed when you start individually marking the birds.

If you just see even a single Spotted Flycatcher after 1 June this year, it will be worth following up. Do you know of a pair nesting near you this year, or of a traditional site which may be being used again?

with any information you have, including records of single birds; and please provide a map reference, preferably to 100m (as TL000000). Follow your leads up and keep us informed or we can arrange to follow up if you don’t have time yourself.

Michael Holdsworth


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