Atlantic Yellow-legged Gull (atlantis)

(last update: October 12, 2011)

Atlantic YLG adult March

data from: Malling Olsen, K. & Larsson, H. 2004 Gulls of Europe, Asia and North America. London: Christopher Helm.

DISTRIBUTION AND MIGRATION
Breeds sea-cliffs and rocky islands, coastal wetlands and cultivation, often with high cover. Locally on roofs in towns and seaports (Bulgaria, Istanbul); frequently inland. Mediterranean breeding sites occupied Nov-Feb (Isenmann 1976, 1978, Cramp & Simmons 1983, Albrecht 1986b, Goutner 1992, Nankinov 1992a, Gruber 1995, Klein & Buchheim 1997).

Atlantic-Cantabrian population was isolated from the Mediterranean population until twentieth century, when expansion and increase started (A. Bermejo in litt.). Increase less dramatic than in Herring (but strong in France), as mainly fish-eater, not as highly opportunistic. Mainly sedentary. Population of France, Iberia and NW Africa stays in Mediterranean or disperses to W Atlantic coast; W Mediterranean and Atlantic populations mainly sedentary. Autumn census of 10,000-12,000 moulting adults Ebro Delta, S Spain. In winter 180,000 around Iberian Peninsula, of which 30,000 NE Spain (Gerona-Va1encia) and 9,000 Galicia, NW Spain. In France max. 50,000 along Mediterranean coast, 60,000-100,000 Italy, of which 15,000-20,000 Sicily; 12,000 Algeria, 2,340 N Egypt (latter not separated from
Caspian Gull). Balkan and Adriatic population sedentary or dispersing N/ NW to River Danube (Isenmann 1973, 1976, Gallissa 1987, Glutz von Blotzheim & Bauer 1982, Meininger & Sorensen 1992, A. Corso in litt).

SW European, Adriatic and E Mediterranean birds disperse N-W July-Oct. Some reach N, W and C Europe. Earliest influxes to C Europe (first- and second-years) Apr; in May mainly adults and from July larger influxes of all ages. In C Europe commonest large gull in July-Sept. Starts to leave C Europe late Aug/ early Sep; mostly left by early Nov; a very few winter. Max. 5,000 Lake Neusiedler See, Austria, 10,000 Lakes Geneva and Neuenburger; 500 Bodensee, 100 S Poland. Small numbers present throughout the year, mainly immatures. Spread to W European, British and Baltic S Coast and S Scandinavia proved by ringing recoveries of Italian, N Adriatic and inland France/ S Germany birds to N and W Europe N to N and E Denmark and Sweden and W to Great Britain in autumn/ winter. N Iberian birds recovered Great Britain and France. Increase W Europe since 1980 correlated with expansion and range extension along French Atlantic coast. In Great Britain first record 1971. Vanguards mid-June (adults), numbers rising to first peak mid-late July (max. 36 Dungeness). First-years from early Aug. Along River Thames, Essex, peak late Aug - mid-Oct (mainly adults) >500 Mucking; decrease from late Oct until dispersal Dec. Similar peak time French Atlantic coast/ Belgium: late July - mid-Aug, most gone late Oct; sometimes late peak, e.g. 191 on 8 October 1997, Nieuwpoort – de Panne, Belgium. Along French Atlantic coast sometimes outnumbers Herring (max. 1,500 Pas-de-Calais). In Netherlands scarce all year, but most are seen July - Sept, adults preceding juveniles. Recoveries from Netherlands and Belgian ringing programmes reveal origin of W European late-summer birds to be W Mediterranean (Spain and France), arriving after inland migration along river systems in W France.

In S Scandinavia scarce July-Nov; outnumbered there by Caspian Gull. Regular S Sweden (especially Scania) and S Denmark. In Sweden 12 records up to 1997, but since then yearly July - Nov (peak Sept), at most 40 Scania autumn 2000. Similar pattern S Denmark, e.g. a total of 138 1990-1997. In S Scandinavia vanguards here from mid-June, numbers rising Aug to peak Sep. N and W Europe mostly abandoned in winter, except for Germany (especially Niedersachsen and Nordrhein-Westfalen) and Netherlands (max. >50 Limburg Dec 1998). A few winter N to Denmark (Géroudet 1968, 1989, 1992a, Nicolau-Guillaumet 1977, Herroelen 1981, Grant 1983, Schuster et al. 1983, de Mesel 1990, Dubois & Stawarczyk 1991, Dvorak 1991, Yésou 1991b, Dennis 1992, 1995. Gruber 1995, Walker 1995, Bengtsson 1996, Garner & Quinn 1997, Jonsson 1998b, Rasmussen 1998, van den Berg & Bosman 1999, Bijlsma et al 2001, K Fischer, Z. Eckedi, K Sandor & R Schiermacker-Hansen in litt,).
Occurrence in Red Sea area uncertain; at most scarce. Birds with michahellis characters have occurred S to Yemen.

Atlantic Iberian birds sedentary or with limited dispersal, as indicated by recoveries from France (1) and Great Britain (1). Vagrant Estonia (a few), Norway (2), Finland (2), Ice land (3), Canada/ N America S to N Carolina (5) (Cornell et al. 1995, Mactavish 1995, Lewis 1996, Gantlett 1999, V Rauste in litt.).

L. m. atlantis (Azores, Madeira and Canary Islands)
Total population >8,000 pairs (6,000 Madeira/Desertas and 2,000 Azores) (Hagemeijer & Blair 1997). Probably atlantis also breeds along Iberian and Moroccan coastline. Many are sedentary, but some local movements involved, as some W African coast S to Senegambia show characters of atlantis. Also records of subspecifically indeterminate birds S to Gulf of Guinea and Nigeria. Probably vagrant Ireland (Cramp & Simmons 1983, Dubois 2001).