Påverkar ålder och kön mönster i vårmigration hos snösparv (Plectrophenax nivalis)?

• Main Author: Angermund, Anna-karin
• Format: Bachelor Thesis
• Language: Swedish
• Published: Umeå universitet, Institutionen för ekologi, miljö och geovetenskap 2017
• Subjects: Snow bunting; spring migration; differential timing age and sex; banding; plectrophenax nivalis; Natural Sciences; Naturvetenskap; Plectrophenax nivalis; Snow Bunting
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-136144

In many bird species protandry is a common pattern during their spring migration, allegedly this pattern is also present for the passerine species snow buntings (Plectrophenax nivalis). During their spring migration males tends to arrive 3-4 weeks before the arrival of females at the breeding grounds. In this study I have examined if this pattern is reflected in their spring migration as well if there is a differential timing between the age classes for males. I also examined if there is a connection between wingspan and arrival time at Umeå delta for each sex and between the sexes. To make this study possible I captured and banded snow buntings during spring at Umedeltat field station and combined my data with 2012’s data of banded snow buntings from the same station. There was a significant difference in mean capture dates between males and females, with males arriving 1.6 days earlier. There was also a significant difference in mean capture dates between older and younger males, older males arriving 2.7 days earlier. When I examined the wingspan for the sexes I looked at it for each year. During 2017 there was a trend for females that those with longer wingspan arrived earlier than females with shorter wingspan. During 2012 there was a significant correlation; females with longer wingspan arrived earlier than those females with shorter wingspan. There was no correlation between males each year. I also found that in 2017 the mean captures dates for males was later than in 2012. In contrast mean capture dates for females was earlier 2017 than in 2012. My data strongly indicate that protandry is present in snow buntings as well as wingspan may have greater importance for females during their migration than males.