20.500.12556/DKUM-53081 Velikost legla, velikost jajc in fenologija prihoda na gnezdišče pri navadni čigri Sterna hirundo v SV Sloveniji Common Tern's Sterna hirundo clutch size, egg dimensions and phenology of its arrival to the breeding site in NE Slovenia Navadne čigre Sterna hirundo so se v gnezdilni okoliš na območju Drave vračale v začetku aprila. V članku predstavljamo meritve 471 jajc iz 184 gnezd navadne čigre. Povprečna velikost legla je bila 2,55 (mediana = 3, min = 1, max = 4) jajc na gnezdo, povprečna velikost jajc je bila 41,1 x 30,3 mm. Med dvo-, tro- in štirijajčnimi legli ni bilo značilne razlike v povprečni dolžini jajc, v povprečni širini jajc pa so se značilno razlikovala predvsem legla s štirimi jajci. Korelacija med dolžino in širino jajc je bila zelo ohlapna (r = 0,25, p < 0,0001). Dolžina jajc je bila variabilnejša spremenljivka (CV%EL = 4,33) od širine (CV%EB = 2,96). Velikostni vzorci jajc v leglih navadnih čiger se ravno ne ujemajo s hipotezo manjšanja legla (brood-reduction hypothesis), pokateri je vsako izleženo jajce znotraj enega gnezda manjše od predhodnega. Common Terns Sterna hirundo began to return to their breeding sites on the Drava river in early April. The article presents the measurement of 471 Common Terns' eggs from 184 nests. Average clutch size was 2.55 (median = 3, min = 1, max = 4) eggs per nest, with an average egg size of 41.1 x 30.3 mm. There was no characteristic difference in the average egg length between the two-, three- and four-egg clutches. Concerning the average breadth of eggs, characteristic differences were noted particularly in four-egg clutches. Correlation between egg length and breadth was very loose (r = 0.25, p 0.0001). Egg length was more variable (CV%EL =4.33) than egg breadth (CV%EB = 2.96). Size patterns in Common Terns' clutches were not quite consistent with the brood-reduction hypothesis, according to which every egg laid in a single nest is smaller than the previous one. ptice čigre navadna čigra Sterna hirundo prvi pomladanski prihod velikost legla velikost jajc Slovenija severovzhodna Slovenija birds common tern Sterna hirundo first spring arrival clutch size eggs size Slovenia North-eastern Slovenia true true true Društvo za opazovanje in proučevanje ptic Slovenije Slovenski jezik Angleški jezik Znanstveno delo 2015-07-10 19:16:36 2015-07-10 19:16:36 2025-03-27 11:42:06 2019-07-11 08:01:13 2003 0 Ljubljana 0 str. 61-66 št. 117 Letn. 24 2003 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 598.8(497.4) 7679234 13071368 0351-2851 URN:SI:UM:DK:WRMNUWBC http://www.dlib.si/details/URN:NBN:SI:doc-1A7OZV3X 1 https://dk.um.si/Dokument.php?lang=slv&id=77641 Pedagoška fakulteta 0 0 0