675th stamp blog: 2025 is the Year of the Kestrel

Who isn't familiar with the phenomenon? Along the side of the road, a bird of prey hangs motionless in the air, flapping its wings and searching for food: a 'hovering' kestrel. Unfortunately, this mouse-eater is struggling. That is why Vogelbescherming and Sovon, together with several other organizations, are calling for extra attention for the kestrel in 2025. What do you know about the kestrel?

Kestrel

The common kestrel (Falco tinnunculus) is a bird of prey in the family Falconidae. The scientific name of the species was published in 1758 by Carl Linnaeus in the tenth edition of Systema naturae.

 

Features

An adult is 30 to 38 centimeters tall. The wingspan is 65 to 80 centimeters. The male has a grey-blue head and neck, a reddish-brown back, and wings with dark spots. The tail is bluish-grey and has a black terminal band. The female is identical to the male but has a brown head and neck, transverse bands on the back and wings, and a brown tail without a black terminal band. Body weight: female kestrel: approximately 190-280 grams; male kestrel: approximately 180-230 grams.

 

Voedsel

The food consists mainly of small mammals and birds such as homing pigeons or wild pigeons, as well as smaller bird species. Also insects such as beetles and mice are part of their diet. Kestrels are able to detect urine trails of mice. This allows them to quickly locate and hunt mouse populations.

 

Reproduction

Kestrels do not build their own nests, but often choose an old crow's nest as a nesting site. They also like to use nest boxes that offer a view of an open space where they can forage for food. The clutch consists of four to six white, red, or yellow-grey eggs. The young remain in the nest for 27–35 days. They reach sexual maturity at the age of 10 months.

 

Spread

Kestrels are found throughout a large part of Europe all year round. In the Netherlands and Belgium, it is a relatively scarce breeding bird listed on the Red List. In Scandinavia and Northern Russia, the birds can only be found during the summer. They occur in a variety of places, from meadows and forest edges to cities. The birds are often seen hunting along motorways.  

Behaviour

Kestrels can hover motionless in the air by flying into the wind with rapidly moving wings and a spread tail. This is called 'hovering'. While hovering motionless in one spot, they look down in search of prey. Once they have found it, they dive down. A persistent myth states that the kestrel's hunting is successful because it can detect the UV light from mouse urine. It has long been known that the retinas of birds of prey can register UV rays. However, research in 2013 showed that the lens of the eye transmits only a portion of the UV spectrum. Due to the limited wavelength transmitted, it is argued that this makes no significant difference to hunting success.  

<strong> More info: </strong>

Year of the Kestrel in 2025: https://www.vogelbescherming.nl/actueel/bericht/2025-is-het-jaar-van-de-torenvalk https://sovon.nl/tellen/telprojecten/jaar-van-de-torenvalk