{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,22]],"date-time":"2026-10-22T09:36:48Z","timestamp":1792661808198,"version":"4.5.0"},"reference-count":69,"publisher":"The Royal Society","issue":"1415","license":[{"start":{"date-parts":[[2001,11,29]],"date-time":"2001-11-29T00:00:00Z","timestamp":1006992000000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/royalsociety.org\/journals\/ethics-policies\/data-sharing-mining\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Phil. Trans. R. Soc. Lond. B"],"published-print":{"date-parts":[[2001,11,29]]},"abstract":"<jats:p>\n                    The circadian pacemaking system of birds comprises three major components: (i) the pineal gland, which rhythmically synthesizes and secretes melatonin; (ii) a hypothalamic region, possibly equivalent to the mammalian suprachiasmatic nuclei; and (iii) the retinae of the eyes. These components jointly interact, stabilize and amplify each other to produce a highly self\u2013sustained circadian output. Their relative contribution to overt rhythmicity appears to differ between species and the system may change its properties even within an individual depending, for example, on its state in the annual cycle or its photic environment. Changes in pacemaker properties are partly mediated by changes in certain features of the pineal melatonin rhythm. It is proposed that this variability is functionally important, for instance, for enabling high\u2013Arctic birds to retain synchronized circadian rhythms during the low\u2013amplitude\n                    <jats:italic>zeitgeber<\/jats:italic>\n                    conditions in midsummer or for allowing birds to adjust quickly their circadian system to changing environmental conditions during migratory seasons. The pineal melatonin rhythm, apart from being involved in generating the avian pacemaking oscillation, is also capable of retaining day length information after isolation from the animal. Hence, it appears to participate in photoperiodic after\u2013effects. Our results suggest that complex circadian clocks have evolved to help birds cope with complex environments.\n                  <\/jats:p>","DOI":"10.1098\/rstb.2001.0959","type":"journal-article","created":{"date-parts":[[2002,7,26]],"date-time":"2002-07-26T19:57:35Z","timestamp":1027713455000},"page":"1801-1810","source":"Crossref","is-referenced-by-count":125,"title":["Complex bird clocks"],"prefix":"10.1098","volume":"356","author":[{"given":"Eberhard","family":"Gwinner","sequence":"first","affiliation":[{"name":"Department of Biological Rhythms and Behaviour, Max\u2010Planck Research Centre for Ornithology, Von\u2010der\u2010Tann-Strasse 7, D\u201082346 Andechs, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Roland","family":"Brandstatter","sequence":"additional","affiliation":[{"name":"Department of Biological Rhythms and Behaviour, Max\u2010Planck Research Centre for Ornithology, Von\u2010der\u2010Tann-Strasse 7, D\u201082346 Andechs, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"175","published-online":{"date-parts":[[2001,11,29]]},"reference":[{"key":"p_9","doi-asserted-by":"publisher","DOI":"10.1177\/074873040001500106"},{"key":"p_10","doi-asserted-by":"crossref","unstructured":"Ariens Kappers J. 1993 Inner ation of the ertebrate pineal gland. 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