Almendralejo

Lesser kestrel: our urban falcon, our treasure

Lesser kestrel (Falco naumanni) is the diurnal raptors most closely-related to the human beings, because of the development of a mutually beneficial relationship after years of evolution. But this relationship began to become very weak in the second half of 20th century. Current, several conservation measures are being developed to protect this raptor but more needs to be done…

Lesser kestrel

This small falcon is 29-32 cm. Male has grey head, uniform rusty upperparts, buff underparts with black spots. Grey band from carpal to tertials and black flight feathers. Grey tail with black subterminal band. Female and immature rusty with black barring and streaking and paler underparts. They have white nails.

Cernícalo primilla
Lesser kestrel (Falco naumanni) (Photo: http://www.avibirds.com)

Common kestrel (Falco tinnunculus) is a similar species, but it is larger. Male lacks grey band on wing and has black spotting on upperparts and moustachial stripe. They have black nails.

Cernícalo vulgar
Common kestrel (Falco tinnunculus) (Photo: http://www.avibirds.com)

The lesser kestrel is a species with no recognized subspecies. Genetic evidence suggests that despite their similar appearance the lesser kestrel is not closely related to the common kestrel.

Diet of lesser kestrel is based on insects, and small mammals in smaller quantities (mice and others micro-mammals).

It lives in regions where the weather conditions are warm and dry with open ecosystems such as steppes and growing areas with high density of preys (mainly insects, coleopteras as beetles, and orthopteras such as crickets and gasshoppers).

This is a migratory species that come back to Africa in February-March to breed. In breeding season, lesser kestrel lives in rural areas and breeds in cavity walls, holes or under shingle roofs in old buildings in our cities and villages. Breeding and hunting behaviors are conducted in group because is a gregarious species and they live in colonies.

Females lay between 3 to 6 eggs, in April-May, both the female and male incubate the eggs for 28-30 days. When chicks are 30-35 days old, they start to hunt and fly reducing their dependency on the food provided in the nest. In September-October lesser kestrels will travel thousands of kilometres to their wintering areas in Africa.

LESSER KESTREL’S HISTORY

The species began to occupy human buildings for many centuries, shifting from historical breeding sites (shelves and slopes) to humanised areas. This continuous evolution proved to be very important advantanges in increasing their populations. Their distributional range was raised because of the buildings available for breeding, and they also discovered  the humanized areas were a perfect protection from predators. Human-altered landscapes around the villages as a result from activities related to agricultural and livestock, were a perfect habitat to find a huge amount of food for adults and their chicks.

However, this biological alliance was also beneficial for humans who found a strategic ally in protecting crops against pests.

Hábitat cernícalo primilla
Hábitat of lesser kestrel in Nees Karyes (Grecia) (Photo: M.Tάλη, http:/www.life-kirkinezi.gr)

However, this situation changed in the second half of 20th Century when populations decreased significantly by human activities.

WHERE IS IT AND WHAT IS ITS SITUATION?

The lesser kestrel is one of the most endangered bird species in the world. Since the 2nd half of 20th Century, the populations of this migratory bird of prey have decreased more than 90% in many European countries.

This species is a migratory small falcon distributed in the Palaearctic south. The palaearctic area is the largest ecozone which the earth is divided. In this area there are boreal and temperate ecosystems, and includes Europe, north of Himalayas in Asia, north Africa and middle and north of the Arabian Peninsula.

Spain holds the most important breeding population in Europe, followed by Turkey, Greece and Italy. The European and Asian populations are fully migratory to Sub-Saharan Africa, from Senegal, Mauritania and West Mali and Niger to Eastern and Southern Africa.

Distribución cernícalo primilla
Global distribution of lesser kestrel  (Falco naumanni) (Photo: BirdLife Internacional)

WHAT IS THEIR THREATS AND HOW CAN WE PROTECT THEM?

The main cause of the decline of the lesser kestrel populations in their Palaearctic breeding grounds has been habitat degradation, mainly because of agricultural intensification and the associated land use changes. The replacement of grazed grasslands, extensive dry cereal and pulses with taller and denser crops (e.g. sunflower, maize, vineyards and other perennial crops) has lead to two important pressures: reduced abundance of large insects and decreased access to prey. The use of pesticides reduced prey populations futher.

Other threats are:

  • Loss of suitable breeding sites due to the abandonment and collapse of rural buildings (e.g. farm houses, towers,…), restoration works of old buildings which cause loss of nesting sites and important disturbance during the breeding season. The solution could be to provide alternative nesting sites but they also it is necessary a regular maintenance (cleaning, restoration) or replacement.
  • Increased brood mortality due to deliberate destruction of nest sites despite of the legal protection and nest predation in some populations. Loss of pre-migration roosting sites and electrocution in power lines, wind farms or linear infrastructures are factors increasing the adult mortality.
  • Reducing juvenile survival and recruitment due to rainfall in Sahel wintering area, pesticides use in Africa, and habitat degradation along migration and stop-over sites.

This species is included in the Annex I of the Birds Directive, in the list of Ornis Committee, and has a Species Action Plan in the European Union. In Spain, is included in the List of Wild Species under Special Protection and in the Red Book of Bird is listed as Vulnerable.

Pollo cernícalo primilla
Chick of lesser kestrel inside a nest under roof. (Photo: Turismo Extremadura)

Conservation measures to protect lesser kestrel populations are:

  • To restore lesser kestrel populations through captive-breeding and release at the right way.
  • To improve, increase and maintain the breeding sites.
  • To improve the foraging habitat by promoting farming practices which favour the lesser kestrel’s prey (mainly insects).
  • To monitor the breeding population of this species at a global level.
  • To raise awareness of environmental activities among different target audiences, on the importance of pseudo-steppe habitats and lesser kestrel populations.
Liberaciones juveniles
Activity of releasing of juveniles to recover from natural nests. (Foto: DEMA)

“Nature is asking for our help, we have to take action!”

REFERENCES

  • Fernández Palacios, J. S. (2004). Lesser kestrel in Andalusia.  Ecological conservation lines. Seville:  Ministry of Environment.
  • Iñigo, A. B. (2010). Action plan for the lesser kestrel Falco naumanni in the European Union. SEO/BirdLife.
  • Madrid, C. d. (1999). Biologist and Conservation of Lesser Kestrel. Madrid: Managing Director of Environmental Development.
  • Wink, M., & Sauer-Gürth, H. (2004). Phylogenetic relationships in diurnal raptors based on nucleotide sequences of mitochondrial and nuclear marker genes. Raptors worldwide. WWGBP, Berlin, 483-498.

Sara de la Rosa Ruiz

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