European pied flycatcher

Appearance

This is a 12–13.5 centimetres long bird. The breeding male is mainly black above and white below, with a large white wing patch, white tail sides and a small forehead patch. The Iberian subspecies ''iberiae'' has a larger forehead patch and a pale rump. Non-breeding males, females and juveniles have the black replaced by a pale brown, and may be very difficult to distinguish from other ''Ficedula'' flycatchers, particularly the collared flycatcher, with which this species hybridizes to a limited extent.

The bill is black, and has the broad but pointed shape typical of aerial insectivores. As well as taking insects in flight, this species hunts caterpillars amongst the oak foliage, and will take berries. It is therefore a much earlier spring migrant than the more aerial spotted flycatcher, and its loud rhythmic and melodious song is characteristic of oak woods in spring.

They are birds of deciduous woodlands, parks and gardens, with a preference for oak trees. They build an open nest in a tree hole, and will readily adapt to an open-fronted nest box. 4–10 eggs are laid.

The very similar Atlas pied flycatcher, of the mountains of north west Africa was formerly classed as subspecies of the European pied flycatcher.

Distribution

The European pied flycatcher has a very large range and population size, and is thus deemed to be of least concern by the IUCN. This species occupies areas of many different countries in Europe, very commonly found in countries of the Iberian peninsula. The species is noted as a vagrant species in places in Northeast Africa and South Asia, such as Sudan and Afghanistan. This flycatcher typically spends winter in tropical Africa.

The European pied flycatcher is a terrestrial bird, typically inhabiting open forests, woodlands, and towns. In 2005, the European population was listed to hold 3–7 million pairs.

Behavior

The male mating behavior has two key characteristics: desertion of the primary female and polyterritoriality. The males travel large distances, an average of 200–3,500 metres, to find his second mate. After breeding with the secondary female, the males return to their first mate. The males of this species are polyterritorial; the males will acquire multiple nest sites to attract a female. Upon breeding with this first female, the male will procure more nesting sites, typically some distance from the site of the primary female, in order to attract a second female for mating. The males that have better success at polygyny are typically larger, older and more experienced at arriving earlier to the mating sites.

The female behaviour has also been studied in depth, especially due to the fact that some females accept polygyny while others are able to maintain monogamous relationships. The first female in a polygynous relationship does not suffer much in comparison to females in monogamous situations. These primary females gain greater reproductive success because they are able to secure full-time help from the male once he returns from his search for a second mate. The second female, however, often suffers from polygyny. These females have 60% less offspring than females that are in a monogamous relationship. These findings are consistent with the polygyny threshold model, which is depicted at the left. Additionally, the secondary female lays a smaller clutch which she is more likely to be able to rear on her own.

Another behavior that is relatively frequent in European pied flycatchers is the practice of extra-pair copulations Thus, the male practicing EPC will have a group of offspring raised successfully without any parental investment on his part. The female may benefit from EPC if the second male is judged to have superior genes to the original male. Another benefit that EPC adds is that there is an increase in genetic variability. However, females are not typically very welcoming of EPC. A female that is being pursued for an EPC will either passively allow the male to copulate with her, or will resist it and risk injury due to the male’s aggression.

Reproduction

In an experiment conducted from 1948 to 1964 in the Forest of Dean in Gloucestershire, two hundred and fifty nest boxes were carefully recorded for their locations and then analyzed for their inhabitance. The median breeding dispersal of the European pied flycatcher ranges from about 52–133 metres , with the average distance between nest sites being about 45 metres . This distance typically depended on the breeding density in each year. The study found little evidence to suggest a difference in breeding dispersal between years or between monogamous and polygynous males. As a result, the data for the separate categories could be combined. The breeding dispersal over longer distances could result in both mate fidelity as well as mate change, the latter of which occurs either while the previous mate is still alive, or following the death of the mate. The breeding dispersal distances of birds that survive more than three breeding seasons were studied, and the results showed that the site fidelity increased with more successive breeding attempts. The same long-term study also found that older European pied flycatchers, both male and female, were more likely to move shorter distances between breeding seasons than younger birds were. When mates were observed to re-establish their pair bond, they tended to occupy certain areas that were near the nest site established in the previous breeding season. In addition, female birds were less likely to return to a former breeding site following the death of, or divorce from, their former partner. When a pair divorces, the females have been observed to move greater distances away than the males. As a result, females that keep the same mates from year to year end up moving shorter distances for each mating period than those that divorce. Divorce has little influence on the likelihood of males moving away from their original nest site. The study found that males that keep the same mate do not move significantly smaller distances than males that divorce.

Food

The main diet of the European pied flycatcher is insects. In fact, their name comes from their habit of catching flying insects, but they also catch insects or arthropods from tree trunks, branches, or from the ground. Studies have found that the majority of food catches were made from the ground. It was also found that airborne prey were captured more during the early part of the season than in the later part ; the converse trend appeared in prey taken from trees. There are also many overlaps in the foraging techniques with the collared flycatcher, the spotted flycatcher, and the redstart.

Courtship feeding, or incubation feeding, occurs when the male feeds the female in the pairing, egglaying stages, and incubation. An interpretation of this behavior is that it strengthens the pair bond between mates.The diet of the European pied flycatcher is composed nearly entirely of insects. One study analyzed the stomach contents of birds during the breeding season and found that ants, bees, wasps and beetles made up the main diet. Ants made up approximately 25% of the diet.
Food given to nestlings include spiders, butterflies, moths, flies, mosquitoes, ants, bees, wasps, and beetles. For Lepidoptera and Hymenoptera, larvae appear to be consumed more than adult insects; the opposite is true for other insect species. There is also variation between the proportions of larvae and adult insects between different habitats. Nestlings were also found to consume more spiders, butterfly, and moth larvae, while adult flycatchers consume more ants.

Evolution

Since most bird species exhibit monogamous mating behaviors, the polygynous behavior of the European pied flycatcher has sparked much research. There are three main hypotheses that seek to explain why females settle polygynously when it lowers their overall fitness and reproductive success compared to a monogamous relationship.