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The use of tongue spots for aging and wing length for sexing Skylarks Alauda arvensis - A critical evaluation

Hegemann, Arne LU ; Voesten, Rob; van Eerde, Kees; van der Velde, Marco and Tieleman, B Irene (2012) In Ringing & Migration 27(1). p.7-12
Abstract
The Skylark Alauda arvensis is a European passerine species lacking plumage dimorphism and having a complete post-nuptial moult in adults, and a complete post-juvenile moult in young birds. Tongue spots were thought to allow age discrimination after moult. Based on data from a study population in the Netherlands, where the age of many birds was known, we show that tongue spots are not useful for ageing Skylarks. Some nestlings lack tongue spots and half of all birds had tongue spots when three years or older. Regarding sex discrimination, males and females can usually be distinguished from a bimodal wing length distribution, but the threshold and amount of overlap in wing length between sexes vary greatly between studies. Here, we show... (More)
The Skylark Alauda arvensis is a European passerine species lacking plumage dimorphism and having a complete post-nuptial moult in adults, and a complete post-juvenile moult in young birds. Tongue spots were thought to allow age discrimination after moult. Based on data from a study population in the Netherlands, where the age of many birds was known, we show that tongue spots are not useful for ageing Skylarks. Some nestlings lack tongue spots and half of all birds had tongue spots when three years or older. Regarding sex discrimination, males and females can usually be distinguished from a bimodal wing length distribution, but the threshold and amount of overlap in wing length between sexes vary greatly between studies. Here, we show that 98% of all individuals from our Dutch breeding population could be sexed correctly by wing length. However, during migration and winter, when populations from other regions co-occur in the same area, molecular analyses revealed that the overlap in wing length between sexes increased. Therefore, ringers need to be cautious when assigning sex, and small males especially are often misclassified. For example, based on criteria used in France, 14% of Dutch male Skylarks, which are partial migrants, would be misclassified as females. (Less)
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author
publishing date
type
Contribution to journal
publication status
published
subject
in
Ringing & Migration
volume
27
issue
1
pages
7 - 12
publisher
British Trust for Ornithology
ISSN
0307-8698
language
English
LU publication?
no
id
b0466655-25b8-4d53-baf6-b153f42f09eb (old id 4732308)
date added to LUP
2014-11-10 09:30:26
date last changed
2016-06-29 09:17:59
@misc{b0466655-25b8-4d53-baf6-b153f42f09eb,
  abstract     = {The Skylark Alauda arvensis is a European passerine species lacking plumage dimorphism and having a complete post-nuptial moult in adults, and a complete post-juvenile moult in young birds. Tongue spots were thought to allow age discrimination after moult. Based on data from a study population in the Netherlands, where the age of many birds was known, we show that tongue spots are not useful for ageing Skylarks. Some nestlings lack tongue spots and half of all birds had tongue spots when three years or older. Regarding sex discrimination, males and females can usually be distinguished from a bimodal wing length distribution, but the threshold and amount of overlap in wing length between sexes vary greatly between studies. Here, we show that 98% of all individuals from our Dutch breeding population could be sexed correctly by wing length. However, during migration and winter, when populations from other regions co-occur in the same area, molecular analyses revealed that the overlap in wing length between sexes increased. Therefore, ringers need to be cautious when assigning sex, and small males especially are often misclassified. For example, based on criteria used in France, 14% of Dutch male Skylarks, which are partial migrants, would be misclassified as females.},
  author       = {Hegemann, Arne and Voesten, Rob and van Eerde, Kees and van der Velde, Marco and Tieleman, B Irene},
  issn         = {0307-8698},
  language     = {eng},
  number       = {1},
  pages        = {7--12},
  publisher    = {ARRAY(0x9524a08)},
  series       = {Ringing & Migration},
  title        = {The use of tongue spots for aging and wing length for sexing Skylarks Alauda arvensis - A critical evaluation},
  volume       = {27},
  year         = {2012},
}