@article{Hågvar_Glesne_Østbye_2009, title={Food habits and niche overlap in three alpine passerine birds, South Norway}, volume={32}, url={https://boap.uib.no/index.php/ornis/article/view/159}, DOI={10.15845/on.v32i0.159}, abstractNote={<p class="MsoNormal" style="margin: 0mm 0mm 0pt; mso-layout-grid-align: none;"><span style="mso-ansi-language: EN-GB;" lang="EN-GB"><span style="font-size: small;"><span style="font-family: Times New Roman;">The three most common passerine birds in alpine habitats on the Hardangervidda plateau, South Norway, are </span></span></span><span style="mso-ansi-language: EN-GB;" lang="EN-GB"><span style="font-size: small;"><span style="font-family: Times New Roman;">the Meadow Pipit <em>Anthus pratensis</em>, the Wheatear <em>Oenanthe oenanthe</em>, and the Snow Bunting <em>Plectrophenax </em></span></span></span><span style="font-size: small;"><span style="font-family: Times New Roman;"><em><span style="mso-ansi-language: EN-GB;" lang="EN-GB">nivalis</span></em><span style="mso-ansi-language: EN-GB;" lang="EN-GB">. Analyses of stomach content showed that invertebrates are the main food of these species, but the</span></span></span></p><p class="MsoNormal" style="margin: 0mm 0mm 0pt; mso-layout-grid-align: none;"><span style="mso-ansi-language: EN-GB;" lang="EN-GB"><span style="font-size: small;"><span style="font-family: Times New Roman;">Wheatear and the Snow Bunting also eat <em>Empetrum </em>berries, and the Snow Bunting becomes a seed eater in </span></span></span><span style="mso-ansi-language: EN-GB;" lang="EN-GB"><span style="font-size: small;"><span style="font-family: Times New Roman;">October when snow has arrived and the two other species have left the area. Seasonal changes in diet were </span></span></span><span style="mso-ansi-language: EN-GB;" lang="EN-GB"><span style="font-size: small;"><span style="font-family: Times New Roman;">related to phenological changes in the availability of food items. Adult Tipulidae were for instance taken by </span></span></span><span style="mso-ansi-language: EN-GB;" lang="EN-GB"><span style="font-size: small;"><span style="font-family: Times New Roman;">all species during the swarming period in July. Overlap in food choice was considered medium for all three </span></span></span><span style="mso-ansi-language: EN-GB;" lang="EN-GB"><span style="font-size: small;"><span style="font-family: Times New Roman;">species combinations. The Snow Bunting overlapped only slightly with the two other species in altitudinal </span></span></span><span style="mso-ansi-language: EN-GB;" lang="EN-GB"><span style="font-size: small;"><span style="font-family: Times New Roman;">distribution, habitat choice and territory. However, the Meadow Pipit and the Wheatear overlapped strongly in </span></span></span><span style="mso-ansi-language: EN-GB;" lang="EN-GB"><span style="font-size: small;"><span style="font-family: Times New Roman;">these parameters. Since their reproduction was successful, we assume that these two species can live together</span></span></span></p><p class="MsoNormal" style="margin: 0mm 0mm 0pt; mso-layout-grid-align: none;"><span style="mso-ansi-language: EN-GB;" lang="EN-GB"><span style="font-size: small;"><span style="font-family: Times New Roman;">with strongly overlapping niches due to a surplus of available invertebrate food. All three species are able to </span></span></span><span style="mso-ansi-language: EN-GB;" lang="EN-GB"><span style="font-size: small;"><span style="font-family: Times New Roman;">change their food choice rapidly and are thus well adapted to manage unpredictable conditions in a harsh, high </span></span></span><span style="mso-ansi-language: EN-GB;" lang="EN-GB"><span style="font-size: small;"><span style="font-family: Times New Roman;">altitude ecosystem.</span></span></span></p>}, journal={Ornis Norvegica}, author={Hågvar, Sigmund and Glesne, Ola and Østbye, Eivind}, year={2009}, month={Jan.}, pages={56–73} }