EURASIAN HOBBY

Falco subbuteo
alcotán europeo
English: Eurasian Hobby.
German: Baumfalke.
French: Faucon hobereau.
Order: Falconiformes.
Family: Falconidae.
29-33 cm
The adult specimen can be distinguished from other small hawks by its lower parts tinted with a reddish color. The juvenile specimen is similar to a Peregrine Falcon (Falco peregrinus), being the Hobby, smaller in size.
Size, while not the most stable characteristic, allows for sexing smaller males, with a wing always smaller than 245mm, so specimens measuring above this can be of either sex. The adult male tends towards intense blue-gray tones on the back. The leggings and under-tail coverts are unspotted or subtly spotted and always of an intense reddish color. The adult female usually has a more subdued blue-gray on the back. The leggings and under-tail coverts with marked spotting. Even with these guidelines, sexing is sometimes difficult due to significant overlap.

In juvenile specimens, the male generally has small and scarce marks on the under-tail coverts. The lower parts are tinted with a slight orange hue. From R3 to R5, the light band is situated close to the subterminal band and generally interrupted on the rachis by a narrow, dark line. The juvenile female displays under-tail coverts with abundant and large spots. The color is duller in her under-tail coverts, without orange hues. From R3 to R5, the light band is situated close to the subterminal band, generally interrupted on the rachis by a wide and dark line.

The described design of the rectrices is useful for sexing 2nd-year specimens, provided these feathers have been retained from the juvenile generation. In juveniles and 2nd-year specimens, there is also significant overlap, so sexing these ages is not always possible.
It is possible to recognize 4 different ages:

Juvenile specimen: Juvenile specimen: wing feathers and upper parts are bathed in a black-brown tone adorned with buff. Under-tail coverts and leggings are light buff, and the central pair of rectrices has tips of the same color. The remaining rectrices are barred with buff tips. Large secondary coverts and primary coverts have a buff edge. The cere and orbital ring are gray-blue.

2nd-year spring: presents plumage similar to the adult or with mixed retained juvenile feathers from the previous generation. Rectrices usually have a mixture of juvenile and adult-type feathers. Large coverts and flight feathers of the juvenile generation (in summer, sometimes with a few newly molted adult feathers).

Adult specimen: with mantle feathers and upper parts of gray-blue tones. Under-tail coverts and leggings are reddish. The central pair of rectrices lacks a buff-colored tip, and the rest of the rectrices have a grayish tip. Large coverts and primary coverts without a buff edge. The cere and orbital ring are yellow.

Some adult specimens may retain secondaries with an adult-type pattern but will never have juvenile wing coverts.
The Eurasian Hobby undergoes a complete postnuptial molt, starting in breeding areas, suspended during migration, and completed in wintering areas. On the other hand, post-juvenile molt is a partial process in winter, changing part of the body feathers and sometimes some rectrices and wing coverts.
Primaries: 10 per wing.
Secondaries: 14 per wing.
Rectrices: 12.
Link: http://blascozumeta.com/

La obtención de este material ha sido posible gracias al permiso necesario de la Generalitat de Cataluña.

Centre de Fauna de Vallcalent

Medidas/Measures

alcotán europeo
Adult specimen:
Beak tip to pupil center: 27mm
Tarsus: 34mm

Adult specimen

 

1.- Primary of the right wing. 2.- Details of the inner vane of the outer primaries. 3.- Details of the inner vane of the inner primaries. 4.- Details of the tip of P10, P9, P8, P7, P6, and P5. 5.- Details of the tip of P4, P3, P2, and P1. 6.- Details of the inner vane of P8, P7, and P6. 7.- Details of P4, P3, and P2. 8.- Details of the tip of P3, P2, and P1. 9.- Details of P10. 10.- Primary of the right wing. 11.- Details of the outer vane of the primaries. 12.- Details of the shaft of the primaries. 13.- Details of the outer vane of the outer primaries. 14.- Secondaries (S1-S7). 15.- Secondaries (S8-S14). 16.- Details of the inner vane of S1, S2, S3, and S4. 17.- Details of the tip of S1, S2, and S3. 18.- Details of the inner vane of S4, S5, S6, and S7. 19.- Details of the inner vane of the secondaries. 20.- Details of the secondaries. 21.- Details of the secondaries and tertials. 22.- Details of the tertials. 23.- Secondaries and tertials of the right wing. 24.- Details of the outer vane of the secondaries. 25.- Details of the tip of the secondaries. 26.- Details of the outer vane of the secondaries. 27.- Details of the shaft of the secondaries. 28.- Details of the tertials. 29.- Primaries, secondaries, and tertials of the right wing. 30.- Primaries, secondaries, and tertials of the right wing. 31.- Primaries, secondaries, and tertials. Primary coverts + greater secondary coverts. 32.- Details of the primary coverts. 33.- Details of the primary coverts. 34.- Details of the greater secondary coverts. 35.- Details of the greater secondary coverts. 36.- Details of the greater secondary coverts. 37.- Primaries, secondaries, and tertials. Primary coverts + greater secondary coverts + median secondary coverts. 38.- Details of the median secondary coverts. 39.- Primaries, secondaries, tertials. Primary coverts and secondary coverts (G, M, and L). Alulas. 40.- Details of the secondary coverts. 41.- Primary coverts. 42.- Greater secondary coverts. 43.- Alulas. 44.- Separators. 45.- Rectrices. 46.- Details of the inner vane of the rectrices. 47.- Details of R1. 48.- Rectrices. 49.- Details of the tip of the rectrices. 50.- Details of the rectrices. 51.- Details of the shaft of the rectrices. 52.- Rectrices + uppertail coverts. 53.- Details of the uppertail coverts. 54.- Uppertail coverts. 55.- Rectrices + undertail coverts. 56.- Details of the undertail coverts. 57.- Undertail coverts. 58.- Mounting of the right scapula. 59.- Feathers of the right scapula. 60.- Mounting of the right flank. 61.- Feathers of the right flank. 62.- Top: Greater primary infracoverts. Bottom: Median primary infracoverts. 63.- Greater secondary infracoverts. 64.- Feathers of the right axilla. 65.- Top: Mounting and feathers of the chest. Bottom: Feathers of the lower belly. 66.- Top: Mounting and feathers of the nape. Bottom: Mounting and feathers of the mantle. 67.- Mounting and feathers of the right leg. 68.- Mounting and feathers of the crown. 69.- Top: Feathers of the throat. Bottom: Feathers of the right ear. 70.- Top: Feathers of the right eyebrow. Bottom: Feathers of the malar.

 

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