Pied flycatchers can see in the ultraviolet spectrum and females use this ability to choose mates. Males also use ultraviolet reflection to visually inspect the eggs his mate has laid. Eggs that reflect in the ultraviolet spectrum receive more parental investment from male parents. Pied flycatchers also use song, plumage color, and egg color to send signals to each other.
Communication Channels: visual ; acoustic
Perception Channels: visual ; ultraviolet; tactile ; acoustic ; chemical ; magnetic
Pied flycatchers have a massive range extending to about 10,000,000 square kilometers. Their population levels are also large, around 24,000,000 to 39,000,000 birds in Europe. Population trends haven't been carefully studied, but BirdLife International does not believe they are declining at a significant rate. Therefore, they are listed as "Least Concern" by the IUCN Red List.
US Migratory Bird Act: no special status
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: least concern
There are no known adverse effects of pied flycatchers on humans.
Pied flycatchers eat the larvae of moths and other pests, including Eugraphe subrosa, Syngrapha interrogationis, Cerastis rubricosa, and Polia hepatica, which feed on plants in the genus Vaccinium, such as bilberry, cowberry, cranberry, and blueberry. Pied flycatchers also eat many other insects and spiders.
Positive Impacts: controls pest population
Pied flycatchers are subject to a range of parasitic infections. The white patches on their foreheads and wings lack the protection of melanin, so those areas are more prone to breakage, bacterial infection, and lice infestations. Pied flycatchers carry infestations of mites and fleas.
Nestlings are parasitized by blow fly larvae (Protocaliphora azurea). Well-fed nestlings are more resistant to parasitism. Blood parasite infections increase in parents with large clutches. Haemoproteus balmorali affects males more, while Haemoproteus pallidus affects females. The increased infection rate is probably due to the birds spending their energy on feeding their young at a cost to their immune systems.
Pied flycatchers have a varying relationship with northern wood ants (Formica aquilonia). When they nest in trees containing these ants, their nests are at risk of predation from the ants. However, when there is another predator which may eat the nestlings, like Eurasian jays (Garrulus glandarius), pied flycatchers may choose to nest in trees with wood ants because they help to defend against jays.
Mutualist Species:
Commensal/Parasitic Species:
Pied flycatchers often catch their prey in the air. They are insectivorous and eat many types of invertebrates, including beetles, spiders, and caterpillars. They also eat flies, ants, bees, and wasps, moths and their larvae. Individuals in populations in polluted areas eat more larvae and fewer moths and spiders than in populations in less polluted areas.
Interestingly, pied flycatchers are not fooled by eyespots on butterfly wings. They will attack butterflies with and without eyespots at equal frequencies.
Animal Foods: insects; terrestrial non-insect arthropods
Primary Diet: carnivore (Insectivore , Eats non-insect arthropods)
Pied flycatchers breed all over Europe, extending into the subalpine regions. They arrive on their breeding grounds in May and migrate to the tropical west African coast, between the equator and 15 degrees north, for the winter.
Biogeographic Regions: palearctic (Native ); ethiopian (Native )
Pied flycatchers winter on the tropical coast of west Africa. In the breeding seasons pied flycatchers are found in forests, and forest composition varies by region. In central Europe, pied flycatchers prefer high altitude beech and spruce forests. They are also found at middle altitude levels, where beech and spruce mix with deciduous forest. Breeding in the middle altitude zone brings them in contact with collared flycatchers (Ficedula albicollis), which prefer low altitudes and deciduous trees. These sister species are normally separated by altitude, tree species preference, and foraging strategy; pied flycatchers prefer foraging near the ground, while collared flycatchers prefer the canopy. However, these two species still produce hybrids at a rate of 2.6% where they co-occur.
In Finland, pied flycatchers prefer large patches of dense, old-growth forest containing deciduous trees and Scots pine (Pinus sylvestris). Territories with deciduous trees proved better in this case, since they provided more food.
Habitat Regions: temperate ; tropical ; terrestrial
Terrestrial Biomes: forest ; mountains
Aquatic Biomes: coastal
Pied flycatchers can reproduce until they are 6 years old, few birds reproduce after that age. The oldest recorded bird was found in Finland, aged 10 years and 11 months old.
Range lifespan
Status: wild: 131 (high) months.
Pied flycatchers are small passerines, weighing about 13 grams. They are darker dorsally and lighter ventrally, with white bars on the dorsal sides of their wings. They often hold their wing tips lower than their tails, which is normal for flycatchers. Females and immature males are light brown ventrally and dark brown dorsally. The plumage of males darkens as they age, until they reach a jet black color. Male plumage reflects ultraviolet light. During nesting, brooding females have an incubation patch which can be used to determine sex.
Male birds have white spots on their foreheads, just above their beaks. The size of these spots directly correlates with a male’s attractiveness to a female. The size also indicates the male’s immune competence, and larger patches are correlated with fewer trypanosome infections. Usually males are the only ones with white forehead patches, but in some populations females may have them as well. These populations are generally in the southern parts of their range, and the patch is a sign of ageing, rather than health.
Insectivores, like pied flycatchers, generally have intermediate basal metabolic rates when compared to similar birds eating different diets. Temperate species average higher basal metabolic rates (BMR) than tropical species, and flighted birds are higher than flightless ones. There are other factors influencing the BMRof a species, including plumage color. Pied flycatchers average about 0.84 kJ/h in BMR.
Average mass: 13 g.
Average length: 13 cm.
Average wingspan: 22 cm.
Average basal metabolic rate: 0.84 kJ/h cm3.O2/g/hr.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: sexes colored or patterned differently; male more colorful
Groups of pied flycatchers respond to predators by mobbing them. Whichever bird spots the intruder will send out a mobbing call to alert the other flycatchers. If the intrusion is serious enough, several pied flycatchers will group together and harass the predator until it leaves. While this is a good strategy for large groups with many possible recruits for the mob, it can be dangerous for birds in less dense living situations. Predators like martens (Martes) may learn the mobbing call and respond to it, coming to attack the nests of birds while they are busy attacking the original intruder.
Stoats (Mustela erminea), least weasels (Mustela nivalis), and martens (Martes) raid nests. Goshawks (Accipiter gentilis), Eurasian sparrowhawks (Accipiter nisus), and tawny owls (Strix aluco) prey on fledgling and adult pied flycatchers.
Mobbing is reciprocal. When a bird hears the mobbing call, it may choose to assist or not. Assisting in mobbing behavior is dangerous, so some birds choose not to help their neighbors. However, birds who do not help in mobbing are significantly less likely to be helped if their nests are threatened.
Known Predators:
Both monogamy and polygyny occur in this species. When a male has two mates, he usually keeps two separate territories, but sometimes both females will coexist in one territory, sometimes even on the same nest. Single females lay 5 to 7 eggs, two females laying together can produce double the eggs. Despite having so many eggs, however, females that nest together only average 1.1 more offspring than monogamous females. In bigynous systems with two territories, the primary female fares better than the secondary female, who may have been tricked into mating with an already paired male. The male usually provides more for his primary mate than the secondary mate, and sometimes he abandons his secondary mate altogether.
Polygyny may also represent a cost to males. Polygynous males are more likely to have unhatched eggs. They are also more likely to be cheated on by one or both mates, causing them to expend energy raising chicks that aren’t theirs.
Secondary female mates may receive a benefit from mating with an already paired male in the form of good genes. This is consistent with the “sexy son” hypothesis and suggests that sons inherit their father’s attractiveness and get more mates, resulting in the same number of grandchildren as the primary female. There is no evidence of this "sexy son" hypothesis in pied flycatchers. Huk and Winkel (2006) found sons of polygynous males were more reproductively successful, but this was true only for sons of primary females, not secondary female mates.
Males use songs to attract females. Bright plumage and complex songs indicate better fitness, so they are preferred by females. Their plumage is even ultraviolet reflective to make it bright to the females’ eyes. One of the best and quickest ways to judge males in an area is to listen to their songs, since the best males arrived first and got the best territories.
Males arrive first in breeding areas and set up their territories. They nest in holes or in nest boxes. They must defend their locations from other males, so they stay near the nest hole. Since they can’t move far from the nest hole without risking the loss of their spot, females are the ones who peruse available males and choose mates. Females generally choose older males first, who are identified by their jet black and white plumage instead of the brown, grey, grayish brown, and light black plumage of younger males. Older males are most likely to become polygamous.
Mating System: monogamous ; polygynous
It appears pied flycatchers not only prefer to nest in boxes, but are more successful when they do. Females begin laying eggs one or two days earlier and lay more eggs when in nest boxes. Larger clutch size is probably due to greater space, since clutch size is correlated with the area of the bottom of the nest. They experience less predation, possibly because the entrance to the box is higher than the actual nest. In natural holes, the entrance may be closer to the nest, making contents easier to access. If given enough nest boxes, these birds will nest at densities up to 200 pairs per square kilometer. In natural nests with optimal settings, they will only nest at densities at a quarter of that level. Breeding success in nest boxes ranges from 72% to over 80%, whereas in natural nests success is usually 54%.
Pied flycatchers lay 6 to 7 eggs which are 17 mm long and 13 mm wide. Eggs weigh about 1.7 grams, about 5% of that is the mass of the shell. The female incubates for 13 to 15 days. Young are altricial at hatching, with a thin covering of down. They fledge 16 to 17 days later.
Breeding interval: Pied flycatchers mate once a year, beginning in May.
Breeding season: Pied flycatchers breed from May into July.
Range eggs per season: 6 to 7.
Range time to hatching: 13 to 15 days.
Range fledging age: 16 to 17 days.
Average age at sexual or reproductive maturity (female): 1 years.
Average age at sexual or reproductive maturity (male): 1 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous
Some females will lay their eggs in another female’s nest. Intraspecific nest parasitism is rare for pied flycatchers, and females guard their nests vigorously to avoid having to raise a chick that is not their own. Females are most aggressive toward each other in the nest building and egg laying phases of their reproductive cycles.
Some females reduce their clutch sizes by removing an egg. They place the egg on the rim of the nest, where it cools until the embryo is dead. Ejections most commonly occur after a particularly cold day. Females who eject eggs are more likely to overlap reproduction and moulting, two processes which require a lot of energy and are usually performed separately. Combining reproduction and moulting may indicate the female in question simply isn’t interested in reproduction as much as non-ejecting females. Other females who eject their eggs are either old (over four years) or have poor immune systems, both of which are physiological factors which make females less-than-ideal mothers.
Brood size affects parental investment by determining how much food parents need to supply. Parents often can’t supply enough when they have too many young. Parents with large clutches make more visits to the nest, but they make fewer visits per nestling than parents with smaller clutches. They don’t bring more food per visit, so each nestling gets less to eat than nestlings in smaller clutches. When presented with too little food, nestlings invest their nutrients in growing muscle and bone, because deficits in these areas are hard to make up later, and they will neglect proper gut development, which can be made up later. Neglecting gut development results in a shorter gut and less absorption abilities, which worsens their undernourishment.
The eggs are blue-green, a color caused by biliverdin, a pigment and an anti-oxidant. The more biliverdin is present in the egg shell, the brighter the egg and the more maternal antibodies it contains. This is important because the better the hatchling's immune system is, the more likely it will grow up healthy and able to reproduce. Laying bright eggs is the female’s way of signaling to her mate that she is healthy and producing good eggs. Deeply colored eggs have young with better immune systems. Eggshells with high levels of immunoglobins even move into the ultraviolet spectrum. Males visit the nest and assess the color of eggs. Males spend more time provisioning young hatched from eggs with good coloring. Male contributions relieve some of the burden on females, allowing her to recover and regain her health after incubation.
Sanz (2001) performed an experiment in which he reduced the size of the white patch on mated males. He found males with smaller white patches (therefore, less attractive males) spent more energy bringing food to their young. The young grew larger than those of unaltered fathers, which shows a clear benefit from the extra provisioning. Females did not change their feeding habits regardless of the males’ attractiveness or effort. The extra effort could be caused by the male being aware he is less attractive and therefore less able to successfully solicit extra-pair copulations, so he invests his time more in parenting.
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Male, Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female); pre-independence (Provisioning: Male, Female, Protecting: Male)
