Bird of the Month – Pied Flycatcher

In the fourth instalment of our “Bird of the Month” blog we look at one of the most iconic summer migrants of Fingle’s Oak woodlands.As April fades into May, the pockets of ancient Oak woodland which nestle between Fingle’s conifers begin to turn a vibrant green, as the unfurling leaves overhead mirror the carpets of Bilberry that cover the ground beneath. For both the resident and migrant bird species that inhabit these woods, this is the most critical part of their year. Over a few short weeks, they must establish a territory, find a mate, build a nest, incubate their eggs and raise a brood of young – all whilst dealing with the unpredictable Dartmoor weather.For one particular migrant species, some of the dedicated team of volunteers who work around Fingle have given them a helping hand by maintaining and monitoring groups of nest boxes in areas of Oak woodland. If you’re walking in the woods in nesting season and spot one of these boxes, take a few minutes to stand at a respectful distance and you might be rewarded by a glimpse of one of the occupants coming and going. The boxes are used by a number of species, so you might see a Blue or Great Tit – but if you are lucky you will spot a small black-and-white bird swooping down from the canopy to deliver a mouthful of insects to its hungry brood before returning to the treetops in search of more food.This unmistakable tree-dweller is a Pied Flycatcher (Ficedula hypoleuca), and a few weeks ago it will have been foraging amongst the forests and farmland of Liberia or Guinea in sub-Saharan western Africa. In late March it will have begun its journey north, crossing several hundred miles of the Sahara Desert in a single non-stop flight, before making its way across western Europe to arrive at Fingle in early April. The timing of the trip is a delicate business – in 2018 their journey north through Europe coincided with the tail end of the “Beast from the East” cold wave. Fewer birds arrived at Fingle that year, with some almost certainly having perished due to the weather.Much of the understanding of the Pied Flycatcher’s migration routes and wintering grounds comes from a long-term European study which includes the East Dartmoor population. As part of this study several birds have been fitted with “geolocators” – tiny devices weighing less than a gram and fitted with a light sensor and an accurate clock which are attached during one breeding season and retrieved when the birds return the following Spring. By analysing the data from these devices researchers can determine the sunrise and sunset times (giving an approximate longitude) and the day length (giving an approximate latitude) and calculate the location of the bird’s wintering grounds to within about 100km.The male Pied Flycatcher is a very striking bird – white underneath and black above, with white wing-bars and a distinctive white forehead mark just above the bill. The female’s plumage follows a similar pattern, but with the black being replaced by a soft brown and a less prominent forehead mark. The male’s song is a series of warbled notes of varying pitches which ends with a short trill. Both sexes also make a loud “whit, whit” call – this is often used when alarmed but also as a contact call with their young once they have fledged.[audio mp3="https://finglewoods.org.uk/wp-content/uploads/2020/06/Pied-Flycatcher.mp3"][/audio] Despite their “flycatcher” name, Pied Flycatchers seldom seem to show the classic flycatcher behaviour of perching on a branch and then darting up to catch insects on the wing. They mainly forage high up in the Oak canopy – in early Spring their diet is predominantly caterpillars and other insect larvae, with spiders featuring more prominently as the season moves on.Their preferred nesting site is a tree cavity – often a knothole a few metres above the ground. As a species however, they have readily adapted to use artificial nest boxes. This adaption has been beneficial for the birds, as it allows for nesting sites to be provided in woodlands with a low number of suitable natural features. It also makes them ideal candidates for studies into breeding and migration behaviour, since they can be monitored and ringed very easily when nesting in boxes.The usual clutch size is seven to nine pale blue eggs, laid in late April. The female will incubate these eggs for around two weeks, with the young remaining in the nest for another three weeks before fledging. It’s not uncommon for males to father two or more broods with different females – if the females are lucky the male will divide his time between helping feed both broods, but there are also cases where one of the females will end up single-handedly raising a brood while the other benefits from all the male’s attention!By late July the young will be independent, and the parent birds will begin departing on their long journey back to Africa. Unlike the Spring migration’s single-minded push north to their breeding grounds, they’ll follow a more relaxed path south, with stop offs in Europe and North Africa. The young birds will remain in the UK for several more weeks, gaining body mass from the abundance of summer insect life, until the shortening days and cold nights of September prompt them to start their own travel towards the winter warmth of Africa.Text, pictures and recordings by Tom Williams