Studying pied flys …part 2

There is much to report, since the first returning pied flycatchers were spotted at Yarner Wood on 5 April. A dedicated team of Natural England volunteers are 4 weeks into their survey of 250 nest boxes around the Reserve, meticulously recording signs of pied flycatchers and other species. And we have been eagerly awaiting news of the 20 male flycatchers, that scientists fitted with tracking devices at the Reserve last year – it is hoped that data from these geolocators will help focus conservation efforts for this species, that has moved from Amber to Red status due to its declining numbers.

A numbered oak nest box –  this is one of the longest running nest box studies in the country; A pied flycatcher nest found in one of the boxes

The pied flycatchers are very active in the woods at the moment and their distinctive smart black and white plumage and calls make them very visible. Once they start constructing their nests, they are rapid nest builders, it takes them just 2 or three days to finish their beautiful nests which they line with finely turned grass. They are a species known to favour nest boxes and it is the monitoring of these boxes that has provided scientists with an invaluable method for studying the ‘pied flys’, as they are affectionately known by scientists.

Last week I accompanied Bryan Thorne from Natural England and one of his experienced volunteer team on their weekly check of boxes. Each of the 250 boxes at the Reserve is numbered and a simple coding system allows volunteers to record what they find in each box – species, stage of nest construction (N1-N4), presence of eggs and whether the eggs are warm. We found a number of beautiful mossy bluetit nests and eggs, they nest earlier than the pied flycatchers. We did find one pied flycatcher nest (N4) at the final stage of construction (N4) and were lucky to spot the female bird close by, carrying nesting material in her beak.

BlueTit nest closeup_KS small
A bluetit nest, their nests are characteristically mossy which helps distinguish them from pied flycatcher nests

In tandem with this long term breeding study, scientists have chosen East Dartmoor NNR for a study to understand more about the wintering sites of pied flycatchers. For scientists Malcolm Burgess (University of Exeter) and Chris Hewson (BTO), their long wait is now over and 10 of their birds tagged last year at the Reserve, have returned. This is a great relief, Malcolm Burgess said ..

“the geolocator work has been very successful. We tagged 20 males last year and have had 10 return. The 50% return rate this year is exactly what we hoped for, as this matches the natural between year survival rate”.

Geolocator screenshot
Scientist, Malcolm Burgess posts regular updates – this tweet on PiedFly.Net shares his excitement at finding one of the geolocators

The next step is to analyse the results from the geolocators and find out where the birds go after breeding. Scientists have to retrieve the geolocators from the birds, as unlike GPS transmitters, data from geolocators can only be obtained directly from the birds’ devices once they return the following year. 5 geolocators have been retrieved so far, and these devices will now be analysed and the details of their journeys will be revealed in Autumn.

The data hidden on the tracking devices could prove key to focussing conservation efforts for the pied flycatcher. The weekly nest box monitoring continues throughout the breeding season and I would particularly like to thank Bryan Thorne of Natural England and Guy Wareham, Natural England volunteer, for sharing their wealth of experience, gained over many years of opening nest boxes and debating over their contents!

For up-to-date reports from the scientists see PiedFly.Net on Twitter – a citizen science network monitoring pied flycatchers, woodland birds and woodland phenology across SW England. Tweets are by Malcolm Burgess

To read Return of the flycatcher – part 1 …Part 3 to follow soon!

Report and photos by Kate Smith, Woodland Trust

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