TY - JOUR AU - Byrkjedal, Ingvar AU - Lislevand, Terje AU - Vogler, Stefanie PY - 2012/09/21 Y2 - 2024/03/28 TI - Do passerine birds utilise artificial light to prolong their diurnal activity during winter at northern latitudes? JF - Ornis Norvegica JA - Ornis Norv. VL - 35 IS - 0 SE - Articles DO - 10.15845/on.v35i0.269 UR - https://boap.uib.no/index.php/ornis/article/view/269 SP - 37-42 AB - <p align="left">&nbsp;</p><p><span style="color: #221e1f; font-size: xx-small;"><span style="color: #221e1f; font-size: xx-small;">Boreal regions with a mild winter climate, such as the western coastal area of Norway, may hold a number of wintering passerine birds, in spite of the short day length in mid winter. To determine whether birds wintering under such conditions were able to use artificial light to increase their activity periods, day-time and night-time bird censuses were done from October to March in a residential area in Bergen, western Norway, along roads lit by street lights. Situated at latitude 60&deg;N, the area has 18 hours of darkness in mid winter. Twenty-four passerine species were recorded. Of these European Robin </span></span><em><span style="font-family: Times New Roman,Times New Roman; color: #221e1f; font-size: xx-small;"><span style="font-family: Times New Roman,Times New Roman; color: #221e1f; font-size: xx-small;"><span style="font-family: Times New Roman,Times New Roman; color: #221e1f; font-size: xx-small;">Erithacus rubecula</span></span></span></em><span style="color: #221e1f; font-size: xx-small;"><span style="color: #221e1f; font-size: xx-small;">, Common Blackbird </span></span><em><span style="font-family: Times New Roman,Times New Roman; color: #221e1f; font-size: xx-small;"><span style="font-family: Times New Roman,Times New Roman; color: #221e1f; font-size: xx-small;"><span style="font-family: Times New Roman,Times New Roman; color: #221e1f; font-size: xx-small;">Turdus merula</span></span></span></em><span style="color: #221e1f; font-size: xx-small;"><span style="color: #221e1f; font-size: xx-small;">, and Eurasian Wren </span></span><em><span style="font-family: Times New Roman,Times New Roman; color: #221e1f; font-size: xx-small;"><span style="font-family: Times New Roman,Times New Roman; color: #221e1f; font-size: xx-small;"><span style="font-family: Times New Roman,Times New Roman; color: #221e1f; font-size: xx-small;">Troglodytes troglodytes </span></span></span></em><span style="color: #221e1f; font-size: xx-small;"><span style="color: #221e1f; font-size: xx-small;">regularly started their activity several hours before sunrise, whereas Great Tits </span></span><em><span style="font-family: Times New Roman,Times New Roman; color: #221e1f; font-size: xx-small;"><span style="font-family: Times New Roman,Times New Roman; color: #221e1f; font-size: xx-small;"><span style="font-family: Times New Roman,Times New Roman; color: #221e1f; font-size: xx-small;">Parus major </span></span></span></em><span style="color: #221e1f; font-size: xx-small;"><span style="color: #221e1f; font-size: xx-small;">and Blue Tits </span></span><em><span style="font-family: Times New Roman,Times New Roman; color: #221e1f; font-size: xx-small;"><span style="font-family: Times New Roman,Times New Roman; color: #221e1f; font-size: xx-small;"><span style="font-family: Times New Roman,Times New Roman; color: #221e1f; font-size: xx-small;">Cyanistes caeruleus </span></span></span></em><span style="color: #221e1f; font-size: xx-small;"><span style="color: #221e1f; font-size: xx-small;">did so to some extent. The other species did not start their activity until morning civil twilight. Measurements of distance from street lights for European Robins during night-time showed that the birds were closer than random to lights. The study shows that some passerine species are able to extend their activity period by 4&ndash;5 hours utilising artificial light during the darkest part of the winter.</span></span></p> ER -