Apus apus

Geographic Range

Common swifts, Apus apus , can be found in almost any region from western Europe to eastern Asia and from northern Scandanavia and northern Siberia to North Africa, Himalayas, and central China. Apus apus can be found throughout this range during the breeding season and, following migration, spends the winter months in Southern Africa, from Zaire and Tanzania south to Zimbabwe and Mozambique.

• Biogeographic Regions
• palearctic palearctic
  • native native
• ethiopian ethiopian
  • native native

Habitat

The majority of the breeding habitat of A. apus is located in temperate zones, where there are suitable trees for nesting and sufficient open spaces in which to fly to gather food. The habitat of Apus apus during the months following migration into Africa, however, is tropical. Common swifts have been observed breeding from sea level to several thousand meters in elevation. Apus apus prefers areas with trees, or buildings with open spaces, and is able to use vertical surfaces such as rock walls and chimneys for nesting due to a unique physical adaptation possessed by all swifts ( Apodidae ).

• Habitat Regions
• temperate temperate
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• forest forest

• Other Habitat Features
• urban urban
• suburban suburban

Physical Description

Common swifts are 16 to 17 cm in length with a wingspan of 42 to 48 cm, depending on the age of the individual. Common swifts are black-brown with the exception of a white to cream colored chin and throat (located directly underneath the beak). In addition, the topside of the flight feathers is paler brown-black in comparison to the rest of the body. Apus apus can also be distinguished by its moderately forked tail feathers, its narrow, sickle-shaped wings, as well as its shrill, screaming call. Apus apus is frequently mistaken for swallows . Apus apus is larger and has very a different wing shape and flight pattern than do swallows. All species in the family Apodidae possess a unique morphological characteristic, a lateral “grasping foot” in which toes one and two are opposed by toes three and four. This allows common swifts to occupy areas such as walls of rock, chimneys, and other vertical surfaces that would be difficult for other types of birds to inhabit. Apus apus is a sexually monomorphic species, meaning that the males and females look alike. There has been no seasonal or geographical variation reported in the appearance. However, it is possible to distinguish juveniles from adults in the slight difference in richness and uniformity of their coloration, as it is common for juveniles to be blacker in color, as well as to have a pale forehead, white-fringed feathers, and a starker white patch under the beak. This distinction is best observed at close range.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• sexes alike

Reproduction

Apus apus usually first breeds at two years of age, but the age of the first breeding can vary based upon the availability of nesting sites. The common swift is a monogamous species, they are faithful to nesting sites each year and to mates during a breeding season. The male A. apus typically chooses the nest site. Upon the arrival of the female shortly thereafter (usually within a period of days), the nesting site is protected by the pair. The nest is typically composed of grass, leaves, hay, straw, and flower petals (among other things). The nesting site usually includes the nest itself and the areas directly surrounding the nest. Courtship, some copulation, and the rearing of the chicks all occur at this site. Colonies of A. apus typically include 30 to 40 nest sites, reflecting the gregarious nature of the common swift mating system. Apus apus is more likely to fight to defend a nesting site than it is to defend a mate. Males attract their female partners through attainment of a good nesting site prior to their meeting. Upon their first meeting it is not unusual for the initial responses of the potential mates, both male and female, to be hostile. If interested and unpaired, the female will enter the nest site tentatively, thereby inviting her potential partner to stroke her chin with its bill. If this encounter is successful, the female may also invite her potential partner to allopreen. Allopreening is the process by which birds smooth or clean each others feathers with their beak or bill. This mutual action begins the pair-bonding process.

• Mating System
• monogamous monogamous

Common swifts typically breed from late April to early May through mid-September when the young are fledged. One of the most unique characteristics of A. apus is its ability to mate while in flight, although they also can mate while on the nest. Mating occurs every few days following the arrival of suitable weather, until a few days after the young have fledged. Following a successful copulation, anywhere from one to four white eggs may be laid, however a clutch size of two is most common. Eggs must then be dutifully incubated for 19 to 20 days while the embryos develop. Both parents participate in the incubation of the clutch. After the young hatch, it can take an additional 27 to 45 days before fledging occurs, usually more than 27 days.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• oviparous oviparous

Both parents take turns incubating the clutch following fertilization and prior to hatching. For the duration of the first week following hatching, the clutch is typically brooded all day long. During the second week, the young are brooded for approximately half of the day. For the remainder of the time, until the clutch is fledged, they are rarely brooded during the day, but are almost always covered at night. Both parents participate equally in all aspects of the raising of the young. In the event that unusually bad weather persists or food sources become scarce during the time shortly after the hatching of the young, the young possess the ability to become semi-torpid, a hibernation-like state, thereby reducing the energy demands of their rapidly growing bodies. This adaptation allows young A. apus to survive with little food for 10 to 15 days. During the time from hatching until fledging, the young are fed almost exclusively in the nest. The young are fed food-balls consisting of insects gathered by the parents during flight and held together with a salivary gland product, creating the food bolus. While the young are smaller, they will share a food bolus among them. However, once young are larger they become able to swallow an entire food bolus on their own.

• Parental Investment
• altricial altricial
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • male
    • female
• pre-weaning/fledging
  • provisioning
    • male
    • female
  • protecting
    • male
    • female

Lifespan/Longevity

Apus apus is typically long-lived. A common swift banded in Sweden was re-trapped at the age of 17. The annual survival rate for the adults is 65-83%.

Behavior

Apus apus is a highly gregarious species. Common swifts typically nest, roost, migrate, and hunt for food in groups throughout the year. In addition, they are unique in their ability to stay aloft for extended periods of time. It is not uncommon for these swifts to spend the entire day on the wing, only landing to feed young or to roost at night. It is estimated that common swifts fly at least 560 miles per day during the nesting season, illustrating their endurance and strength, as well tremendous aerial ability. They can also mate and forage for food while in the air. Common swifts typically fly in lower airspace when the weather is poor (cold, windy, and/or wet), and will move to higher airspaces when the weather is more favorable for extended aerial activity.

• Key Behaviors
• flies
• diurnal diurnal
• motile motile
• migratory migratory
• social social

Home Range

Apus apus has been known to consistently forage more than 48-61 km from nesting or roosting sites.

Communication and Perception

Communication between Apus apus occurs almost exclusively through the use of different vocalizations, or calls, and by changes in body language. The types of calls used by A. apus are largely dependent upon its age. There are different calls used by the adults than by the young. The most common call during flight, a long, shrill ‘sreee’, is used in innumerable contexts by adults. Also among the vocalizations of the adults are those given during allopreening (nest-call), those following defeat in a fight (piping-call), as well as those preceding copulation (pre-copulatory call). The most common call used by young is the food-call, used to beg for food from a parent upon its return.

• Communication Channels
• visual visual
• tactile tactile
• acoustic acoustic

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Common swifts are insectivorous, feeding solely on aerial insects and spiders that it gathers in its mouth as it glides through the air. The insects are gathered together inside the throat through the use of a product from the salivary glands, to form a food-ball or bolus. Apus apus is commonly attracted to swarms of insects, as it aides in the ease of collecting sufficient food. It has been estimated that there are an average of 300 insects per bolus. These numbers may vary based upon the abundance of prey. Among some of the most commonly consumed insects are aphids ( Hemiptera ), wasps, bees, and ants ( Hymenoptera ), beetles ( Coleoptera ), and flies ( Diptera ).

• Primary Diet
• carnivore carnivore
  • insectivore insectivore

• Animal Foods
• insects
• terrestrial non-insect arthropods

Predation

Most notable among the anti-predator adaptations of A. apus is its aerial mastery, allowing these birds to avoid most of their natural predators, including Eurasian hobbies ( Falco subbuteo ), sparrowhawks ( Accipiter nisus ), and buzzards ( Buteo buteo ), by taking to the air. In addition, the choice of nesting sites on vertical surfaces such as rock walls and chimneys makes it difficult for common swifts to be preyed upon because of the level of difficulty associated with accessing the nest area. The plain coloration of Apus apus also is advantageous for predator evasion as it makes them difficult to see when they are not in the air.

Ecosystem Roles

As a predator, A. apus contributes to the control of the insect population.

Economic Importance for Humans: Positive

Besides the fact that the common swift frequently nests in close association with humans, A. apus has no significant economical impact on humans. Apus apus may offer a slight benefit to humans by consuming pest insects such as mosquitos. However, it is unlikely that A. apus itself would have a significant impact on these pest populations. In some places common swifts are encouraged to nest in manmade structures so that the young can be harvested for food, however, this practice is not very common. Also the nests of some swifts are used by indigenous peoples of Asia as the key ingredient in bird’s nest soup.

• Positive Impacts
• food food
• controls pest population

Economic Importance for Humans: Negative

Common swifts have no notable negative impacts upon humans, with the exception of the occasional nuisance of having them nest in the eaves and open spaces in the rooftops of many cities and villages across Europe.

• Negative Impacts
• household pest

Conservation Status

Apus apus is neither threatened nor endangered.

Additional Links

Encyclopedia of Life

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Katie Thompson (author), Kalamazoo College, Ann Fraser (editor, instructor), Kalamazoo College.

References

Bannerman, D. 1955. Order Apodiformes, Sub-Order Apodes, Family Apodidae, Genus Apus. Pp. 1-12 in The Birds of the British Isles , Vol. IV, 1 Edition. Edinburgh: Oliver and Boyd Ltd..

Bruun, B., H. Delin, L. Svensson. 1992. Birds of Britain and Europe . London: Hamlyn Publishing Group Limited.

Johnson, L. 1992. Birds of Europe with North Africa and the Middle East . London: A & C Black.

Svensson, L., P. Grant. 1999. Birds of Europe . Princeton: Princeton University Press.

Terres, J. 1980. Swift Family. Pp. 868-870 in The Audubon Society Encyclopedia of North American Birds . New York: Alfred A Knopf, Inc..

2001. Common Swift (Apus apus). National Audubon Society Sibley Guide to Bird Life and Behavior . New York: Alfred a Knopf, Inc..

1985. Common swift (Apus apus). Pp. 657-670 in The Birds of the Western Palearctic: Birds of Europe, the Middle East, and North Africa . New York: Oxford University Press..

2003. Swifts. Pp. 421-425, 429-430 in Grzimek’s Animal Life Encyclopedia, Second Edition , Vol. 9. New York: The Gale Group, Inc..