The Lesser Kestrel is a migratory species and reaches the areas where it nests in early spring. It chooses to nest next to other Lesser Kestrel pairs forming colonies typically comprising of 15 to 25 pairs. Although the colony provides greater security for its young and facilitates foraging, competition to occupy the most suitable nesting sites is fierce. Consequently, the first birds arriving in the colony have better chances of finding a suitable nest.
The pairs are formed each year in the colony and maintained throughout the breeding season. During courtship the male provides the female with offerings, mainly insects. Once the pair is formed the birds remain at or near the nest, which they protect.
For its nest the Lesser Kestrel selects holes in tall buildings, warehouse and house walls or roofs. In order to construct its nest it does not transfer additional materials. It creates a slight depression, formed probably by the female through twirling and pushing away the existing material using its feet and body. This depression is where it deposits its eggs.
The female lays 3-5 eggs. If the eggs are lost, the female produces others - but no more than 3 eggs. Incubation lasts almost a month. Although mainly the female incubates, the male can also help for some short periods during the day.
Upon hatching the young are taken care of by both parents. Both parents hunt to feed their chicks. The most food, of course, arrives from 10.00-16.00, when the temperatures are high and the insects are more active. Occasionally it is observed that young immature males contribute in rearing a pairs' chicks.
In fifteen days, the fledglings are approaching the entrance of the nest or get out of the nest altogether. A whole month will pass until the young will eventually be capable of flying and leave the nest. The young Lesser Kestrels migrate following their parents 6-8 weeks after they have left their nest, while they can form their own family 1-2 years later.
The birds abandon their colonies when most of the young are independent and by the end of July colonies get empty.
The Lesser Kestrel feeds mainly on insects and in the large majority Orthoptera, such as jacks and crickets (Gryllidae), grasshoppers (Acrididae) and Mole crickets (Gryllotalpidae), as well as Beetles - especially Scarab beetles (Scarabaeidae) and Ground beetles (Carabidae). A family of Lesser Kestrels can consume up to 160 Grasshoppers per day during the period of raising their young.
Apart from insects, Lesser Kesterls also hunts small mammals and lizards.
It is an opportunistic species and exploits the local abundance of insects. The Lesser Kestrel has the ability to hunt its prey both in the air and on the ground. It flies in rural places with good visibility, without many trees - in small groups. Flying a few feet above the ground, it hovers until it finds its prey, swoops and grabs it. It may also catch flying insects in the air. It is one of the few falcons that hunt in groups.
Lesser Kestrel eats while in the air, using its leg to bring the pray to its mouth.
In Europe, the largest numbers of Lesser Kestrels are observed in the northern regions of the Mediterranean. It occurs in flat inland areas with low vegetation of grasses and semi - desert areas, with almost no vegetation. It selects mainly low altitudes: in Europe it nests below 500 m and typically to even lower altitudes, showing however preference mainly to hilly areas.
Its presence highly depends on the existence of large populations of insects, which are its prey. For this reason, in the area of its geographical distribution, where there are high concentrations of insects observed high densities of Lesser Kestrels occur.
Areas that meet its biological needs for food and nesting sites are mainly cultivated plains, and habitats in warm areas with sparse vegetation, where there are plenty of insects to feed on, as well as settlements where it can nest. It its of interest that the Lesser Kestrel is not disturbed by the presence of human - unless hunted.
During the breeding season an important factor is the existence of foraging sites near the colony. Where there are suitable habitats, their movements are often limited to distances of 1-3 km from their nest.
The Lesser Kestrel is a migratory species. The majority of species' individuals winter in sub-Saharan Africa, with only a few preferring southern Spain, north-western Africa and southern Turkey. Large concentrations of Lesser Kestrel are observed in Botswana, Namibia and South Africa.
The spring migration begins in February, with the bulk of birds migrating from mid-February to mid-April, while the main autumn migration lasts from late August to the end of October.
During migration, the Lesser Kestrels fly in small groups or in loose flocks which sometimes reach the size of several hundred individuals at altitudes that reach 2.000 m.
In the Mediterranean region the migration peaks in September and takes place on a wide front.
At the end of summer and before starting their journey back to Africa, where they will overwinter, the Lesser Kestrels gathered in large numbers at roosts. During this period they change plumage and are particularly vulnerable. Large numbers of birds at the roosts provide security.
Those roosts are mainly located in areas of greatest altitude in relation to spawning areas.
In Greece a main roost has been discovered in the city of Ioannina, near the lake, where over 3,500 Lesser Kestrels are concentrated every year in late August.