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Falco naumannilesser kestrel

By Kirsten McDonnell

Geographic Range

The lesser kestrel breeds in the palearctic in Europe and northern Asia roughly between 30 and 50 degrees North latitude. The distribution includes altitudes of up to 500m above sea level. It is a migratory species, spending its winter in Africa, south of the Sahara. From February to April this bird is most numerous in northern Tanzania and southern Kenya.

Habitat

Lesser kestrels are found in bushed, wooded, and open grassland and cultivation. They nest on mountain slopes, gorges, deep ravines, and other rocky terrain, all of which must have open areas around them for the birds to hunt. They are found most numerously in highland farming regions and on grassy plains during the winter range.

Physical Description

This small falcon has a length of 30-36 cm with long pointed wings. The long tail has a broad black terminal band. This falcon has strong sexual dimorphism in its plumage. Males have a chestnut back and a blue-grey crown, neck, rump, and tail. Their belly is a creamy pink with small brown streaks. The eye ring is bright yellow while the feet are an orange-yellow. The undersides of the wings are white with a black tip. Females have a brown back and head with a pale belly. Both the back and belly are streaked with brown. The wings are also light with dark barring and black tips. Juvenile lesser kestrels look similar to the females.

Reproduction

Breeding occurs during the months of March through June. Kestrels do not build nests. Instead they lay their eggs in a depression they scrape in the trees of the nesting location. They breed in colonies of up to 100 pairs. Females invest more time in nesting activities than males. Kestrels have a normal clutch size of 4 to 6, laid over a two day interval, but the range in number of eggs is 1 to 7. Incubation starts after the third egg is laid and lasts 28 to 31 days. Because incubation is delayed until the after the third egg, the first three eggs usually hatch on the same day with the rest following in the next couple of days. This means the last bird hatched is smaller than the rest. The difference in size allows the brood to be reduced by sibling rivalry if sources of food are short. Kestrel nestlings have been seen to kill and eat brood-mates, but most deaths occur because of failure to compete for food. Parents continue to feed their young for 2 to 4 weeks after hatching.

Lifespan/Longevity

Behavior

Lesser kestrels are gregarious, usually found in loose flocks. They roost communally in trees. Sometimes thousands of birds are found together in the same tree. They fly with light shallow wing beats and lots of gliding. Kestrels spend a large amount of time displaying in order to maintain their pair bond and fighting to defend their territory. They migrate singly or in small flocks of 40 to 50 birds at about 2,000m above sea level.

The call is a high-pitched ki-ki-ki-ki-ki-ki-ki.

Communication and Perception

Food Habits

Kestrels are carnivorous, feeding on small mammals, especially voles, however they are very adaptable to other prey selections. They will eat almost anything they can kill. Their selected prey is either the most abundant or most easily caught of the area. Other prey examples are young rabbits, birds, small bats, lizards, snakes, frogs, insects, earthworms, fish, and crabs. Kestrels can change their hunting style depending on the kind of prey, weather conditions, and their energy requirements. These predators take full advantage of their keen eyesight, sharp claws, and strong beak. They hunt from a perch or from the air. The vertebrate prey is pounced on from a rapid dive, then grabbed by the claws and killed by a bite to the base of the skull. Attacks on less active prey results from slow shallow dives where the kestrel lands and takes the prey directly into its beak.

Economic Importance for Humans: Positive

This bird eats mice and insects that damage human crops.

Conservation Status

There still is not complete data on the distribution of the lesser kestrel. This information is needed in order to adequately conserve the species. Important subjects to study include problems with the foraging habitat, pesticide contamination affecting reproduction success and food availability, problems with breeding colonies, winter ecology and how to develop and coordinate an international conservation strategy. The winter distribution seems to be the most unknown.

Trends in the breeding populations of the lesser kestrel clearly show this species is seriously threatened worldwide. This bird is protected by law, but not all of the breeding sites are in protected areas. Legal protection of all sites is necessary for conservation because most of the causes of death are hunting or taking young from the nests.

Estimations of the abundance of the lesser kestrel show that breeding numbers have dropped by 95% since the 1950's. Sharp declines are especially obvious in its European range. A marked decrease in breeding range appeared all over Europe, most notably in Poland, Czechoslovakia, and Austria where lesser kestrels are no longer breeding.

Other Comments

Besides hunting, pesticides and predation are other causes of death in lesser kestrel populations.

Contributors

Kirsten McDonnell (author), University of Michigan-Ann Arbor, Dea Armstrong (editor), University of Michigan-Ann Arbor.

Glossary

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map

Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map

acoustic

uses sound to communicate

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

scrub forest

scrub forests develop in areas that experience dry seasons.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

visual

uses sight to communicate

References

Iankov, P., T. Petrov, T. Michev, L. Profirov. 1994. Past and present status of the Lesser Kestrel Falco Naumanni in Bulgaria. Raptor Conservation Today: 133-137.

Negro, J., F. Hiraldo. 1993. Nest-site selection and breeding success in the Lesser Kestrel Falco Naumanni. Bird Study, 40 (2): 115-119.

Paterson, A. 1991. Lesser Kestrel hunting bats. British Birds, 84 (4): 151.

Village, A. 1990. The Kestrel. London: T & A D Poyser.

Zimmerman, D., D. Turner, D. Pearson. 1996. Birds of Kenya and Northern Tanzania. London: Cristopher Helm.

Zollinger, R., W. Hagemeijer. 1994. The Lesser Kestrel Falco naumanni: review of the status of a globally threatened species. Raptor Conservation Today: 219-228.

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