| Titre : | Lack of correlation between sex ratio and food supply or other biotic variables in nestlings of Tengmalm's Owl Aegolius funereus |
| Auteurs : | Ortwin Schwerdtfeger, Auteur ; Michael Wink, Auteur |
| Type de document : | Article |
| Dans : | Journal of Ornithology (155(2) APR 2014) |
| Article en page(s) : | 497-505 |
| Langues: | Anglais |
| Résumé : | Tengmalm's Owls (Aegolius funereus) (TO) exhibit a pronounced sexual size dimorphism in which females are bigger than males, which have to provide food for the breeding female and for the brood. Clutch size and breeding success are strongly influenced by food supply, especially by the abundance of small rodents. Since 1979, the breeding ecology of TO has been studied in a nest box population in the Harz Mountains. In this study, the influences of food supply and other variables on sex allocation of young TO were analysed. Between 2001 and 2011, all 758 nestlings from 176 broods were sampled. Their sex was determined by DNA analysis (PCR amplification of DNA markers on the sex chromosomes). The mean sex ratio was male-biased with 53.4 % male offspring with yearly variations between 43.3 and 66.7 %. Nestling mortality was independent of sex. Food abundance changed between good and bad years. No correlation could be established between food supply by individual fathers and offspring sex ratio. Neither seasonal variation of hatching dates, the hatching order within a clutch nor individual fitness characters of parents had a significant influence on sex ratios. Yearly sex ratios did not diverge significantly from 50 %. The sex ratio fluctuated to the same degree in 5 good years and in 4 bad years. These results are in contrast to a study in Sweden, where an influence was detected within a 3-year vole cycle of food supply on offspring sex ratio. There, the sex ratio was male-biased in the good year, unbiased in the subsequent year and female-biased in the bad year. |
Bibliothèque Tour du Valat
Se connecter
La Tour du Valat
Institut de recherche pour la conservation des zones humides méditerranéennes- Les publications récentes de la Tour du Valat
- Catalogue en ligne du centre de ressources
- A la une
-
Sélections
- Les écrits de Luc Hoffmann, fondateur de la Tour du Valat
- Des références récentes sur les zones humides méditerranéennes
- Quelques exemples d'impact du changement climatique sur les zones humides
- Quelques références bibliographiques sur la grippe aviaire
- Les recherches de la Tour du Valat sur le saturnisme
- De récentes publications sur la Camargue
- Le fonds Camargue de la bibliothèque
- Coordination géographique
- Nous contacter
Infos pratiques
Heures d'ouverture et contact
Lundi , mardi et jeudi de 9h à 12h et de 13h à 17h00 : ouverture au public ...
Liens utiles
- 1 - Le site Internet de la Fondation Tour du Valat
- 2 - La base documentaire du Pôle-relais lagunes méditerranéennes
- 3 - Le site Internet consacré aux Oiseaux d'eau en région Méditerranée
- 4 - Le site Internet ObsNature Camargue -Crau-Alpilles - recueil de données d'observations naturalistes
- 5 - Le site Internet de MedWet, l’initiative pour les zones humides méditerranéennes
