And Age-Specific Seasonal Dispersal of Herring Gulls Larus Argentatus Breeding in the Netherlands
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Colony- and age-specific seasonal dispersal of Herring Gulls Larus argentatus breeding in The Netherlands C. J. Camphuysen, Harry J. P. Vercruijsse & Arie L. Spaans Journal of Ornithology ISSN 0021-8375 Volume 152 Number 4 J Ornithol (2011) 152:849-868 DOI 10.1007/s10336-011-0664-7 1 23 Your article is protected by copyright and all rights are held exclusively by Dt. Ornithologen-Gesellschaft e.V.. This e-offprint is for personal use only and shall not be self- archived in electronic repositories. If you wish to self-archive your work, please use the accepted author’s version for posting to your own website or your institution’s repository. You may further deposit the accepted author’s version on a funder’s repository at a funder’s request, provided it is not made publicly available until 12 months after publication. 1 23 Author's personal copy J Ornithol (2011) 152:849–868 DOI 10.1007/s10336-011-0664-7 ORIGINAL ARTICLE Colony- and age-specific seasonal dispersal of Herring Gulls Larus argentatus breeding in The Netherlands C. J. Camphuysen • Harry J. P. Vercruijsse • Arie L. Spaans Received: 28 April 2010 / Revised: 28 October 2010 / Accepted: 26 January 2011 / Published online: 6 March 2011 Ó Dt. Ornithologen-Gesellschaft e.V. 2011 Abstract The Herring Gull population in The Netherlands 51–100 km, 14.4% at 101–200 km and 4.1% at went through phases of exploitation, protection, persecution 201–300 km). Colony-specific differences in travelling and again (partial) protection during the nineteenth and distance, dispersal rate and direction of movements suggest twentieth centuries. The numbers of breeding pairs peaked a grouping of colonies in three areas: (1) eastern Wadden in the 1980s at approximately 90,000 pairs, at which point a Sea islands (Rottumeroog–Vlieland), with significantly colour-ringing campaign was organised to evaluate dis- higher dispersal rates and movements mostly towards the persal and distribution patterns. Herring Gulls were ringed south-west to south-east; (2) Texel and the four colonies as chicks, predominately near-fledglings, in 12 colonies in along the mainland coast (Callantsoog–Wassenaar), with 1986 (1,247 individuals), 13 colonies in 1987 (1,354 indi- shorter mean range and movements mostly to the south; (3) viduals) and 14 colonies in 1988 (1,396 individuals). colonies in the Delta area (Europoort–Saeftinghe), with Between 1986 and 2009, of the 3,997 Herring Gull chicks rather short range movements and dispersal in many direc- colour-ringed, 3,124 individuals (78.2%) were seen and tions. The maximum distance travelled did not vary much reported at least once, while 453 (11.3%) were recovered between adults, immatures and juveniles, but the timing of dead. In total, 86,247 ring-readings of living gulls were outward and return movements was different for each of received and processed, originating from 1,358 locations by these age categories. Adult birds reached their greatest mean 868 observers. One-fifth (20.5%) of all sightings originated distances on average 1 month earlier than immatures, which from the home-ranges (areas within a radius of 5 km around in turn arrived at this point 1 month earlier than juveniles. the ringing place). Only 691 sightings (0.8%) were reported These age-specific differences were enhanced in the spring, at over 300 km from the natal colony (10.7% at 6–10 km, when birds were moving towards the (natal) colonies, but 8.9% at 11–25 km, 17.7% at 26–50 km, 22.9% at when adults moved on average closer and 2 months ahead of immatures, which in turn moved earlier and closer to the natal home-range than juveniles. With reference to findings Communicated by P.H. Becker. from other studies in other European countries, Herring Gulls breeding in The Netherlands occupies a mid-position & C. J. Camphuysen ( ) between dispersive and sedentary tendencies. Royal Netherlands Institute for Sea Research (NIOZ), P.O. Box 59, 1790 AB Den Burg, Texel, The Netherlands e-mail: [email protected] Keywords Larus argentatus Á Colour-ringing Á Dispersal Á Timing Á Distribution Á Long-term trends H. J. P. Vercruijsse Girostraat 38, 5038 DN Tilburg, The Netherlands Zusammenfassung Die niederla¨ndische Population der A. L. Spaans Silbermo¨we durchlief wa¨hrend des 19ten und 20ten Jahr- Alterra Wageningen UR, Wageningen, The Netherlands hunderts Phasen der Ausbeutung, des Schutzes, starker Verfolgung und wieder (teilweisen) Schutzes. Die Anzahl Present Address: A. L. Spaans bru¨tender Silbermo¨wen erreichten in den 1980er Jahren Sylvalaan 12, 6816 RB Arnhem, The Netherlands ihren Ho¨chststand bei ca. 90 000 Brutpaaren. In dieser Zeit 123 Author's personal copy 850 J Ornithol (2011) 152:849–868 wurde ein Farbringprogramm initiiert um Dispersions- und Scandinavia and Russia, are known as either resident or dis- Verbreitungsmuster zu untersuchen. Silbermo¨wen wurden persive to a varying degree (Glutz von Blotzheim and Bauer als Ku¨ken, mo¨glichst kurz vor dem Flu¨ggewerden beringt, 1982; Cramp and Simmons 1983). Seasonal dispersal pat- jeweils in 12 Kolonien 1986 (1 247 Ind.), 13 Kolonien terns have been shown to vary with age as well as with 1987 (1 354 Ind.) und 14 Kolonien 1988 (1 396 Ind.). breeding area (Landsborough Thomson 1924; Eaton 1933; Zwischen 1986 und 2009 wurden von insgesamt 3997 als Schu¨z 1933; Coulson and Butterfield 1985; Calladine 2002). juvenil beringten Silbermo¨wen 3124 Individuen (78,2%) In The Netherlands, where the species is generally regarded mindestens einmal lebend zuru¨ckgemeldet, wohingegen as a common resident or at best a short-distance migrant 453 (11,3%) als Totfunde gemeldet wurden. Insgesamt [Commissie Nederlandse Avifauna (CNA) 1970; Bijlsma wurden 86 247 Ablesungen lebender Silbermo¨wen erziehlt et al. 2001], a review of migratory movements and dispersal und bearbeitet, welche von 1358 verschiedenen Orten patterns of Herring Gulls has thus far only been undertaken on und 868 Beobachtern stammen. Ein Fu¨nftel (20,5%) aller the basis of metal ring recoveries (Spaans 1971). Tinbergen Sichtungen beruhen auf Meldungen aus dem Home-Range (1952) reported an apparent discrepancy between the results (Gebiete innerhalb eines Radius von 5 km um den Berin- of an early analysis of ringing results (Drost and Schilling gungsort). Nur 691 Sichtungen (0,8%) wurden aus u¨ber 1940), in which Herring Gulls were described as residents 300 km Entfernung vom Geburtsort gemeldet (10,7% aus with some dispersal in all directions after the breeding season, 6–10 km, 8,9% aus 11–25 km, 17,7% aus 26–50 km, and observations of endless streams of southbound Herring 22,9% aus 51–100 km, 14,4% aus 101–200 km und 4,1% Gulls along the coast, which led him to call for more data. aus 201–300 km). Koloniespezifische Unterschiede in Spaans (1971) also concluded that during the 1950s and Zugdistanzen, Dispersionsrate und Zugrichtung lassen eine 1960s, after the breeding season, Herring Gulls dispersed in Einteilung in drei Gruppen zu: (1) O¨ stliche niederla¨ndische all directions, ‘‘more or less random around the ringing Wattenmeerinseln (Rottumeroog–Vlieland), mit signifikant localities’’, and that only birds from Texel in their first year ho¨heren Dispersionsraten und Bewegungen meist in moved predominantly to the south. Richtung su¨dwest bis su¨dost, (2) Texel und die vier The Herring Gull population in The Netherlands went Kolonien entlang der Festlandsku¨ste (Callantsoog—Was- through phases of exploitation, protection, persecution and senaar), mit ku¨rzeren mittleren Entfernungen und Bewe- again (partial) protection in the late nineteenth and through- gungen, meist nach Su¨den und (3) Kolonien im Deltaareal out the twentieth centuries (Spaans 2007). In the early (Europoort–Saeftinghe) mit eher geringen Entfernungen twentieth century, the breeding population was small und Dispersion in viele Richtungen. Die maximal (approx. 2,500 pairs), and colonies were frequently raided by zuru¨ckgelegten Distanzen zeigen keine starke Variation humans in search of eggs (food) and feathers (fashion). This zwischen adulten, immaturen und juvenielen Tieren, changed around 1912, when protective measures were jedoch zeigten sich unterschiedliche Zeitmuster fu¨r Wegzug implemented to safeguard colonies from egging and other und Ru¨ckkehrbewegungen fu¨r jede Altersklasse. Adulte forms of disturbance and the demand for seabird feathers had Vo¨gel erreichten die gro¨ßte mittlere Distanz im Schnitt come to a halt. The population increased from the mid-1910s einen Monat fru¨her als die Immaturen, welche dieses Sta- to approximately 15,000 pairs in the late 1930s (12.2% dium wiederum einen Monat vor den Juvenilen erreichten. increase per annum; Spaans 1998). By that time, however, Diese altersspezifischen Unterschiede wurden im Fru¨hjahr even conservationists became concerned about the impact of noch vergro¨ßert, wenn die Vo¨gel sich in Richtung ihrer what was called an ‘‘overpopulation’’ of Herring Gulls. Geburtsorte bzw. Kolonien bewegten, wobei sich Adulte Measures to restrict the number of nesting Herring Gulls were im Schnitt na¨her und zwei Monate vor den Immaturen in taken and, in the absence of immediate success, this devel- Richtung der Kolonie begaben, wa¨hrend die Immaturen oped into a systematic campaign of destruction. From 1947 to sich wiederum fru¨her und na¨her in Richtung ihrer 1966, some 90,000 adults were either shot or poisoned, and Geburtsorte begaben, als die Juvenilen. Unter Beru¨cksichti- some 500,000 eggs were destroyed (Spaans 2007). In the mid- gung anderer europa¨ischer Studien, zeigen niederla¨ndische 1960s, this type of destruction came to an end, partially Silbermo¨wen eine Zwischenstellung zwischen dispersieven because the effect of culling was ‘‘disappointing’’, but also und ortsgebundenen Bewegungsmustern. because of an alarming decline in the breeding success of a number of seabirds and marine mammals in the Wadden Sea area due to intoxication following continuous leakages of pesticides (e.g.