Marginal presence of plastic in nests of yellow–legged gulls (Larus michahellis) in the southeastern Bay of Biscay

Nest entanglement and consumption of plastics can be a cause of mortality in chicks of various seabird species. As plastic debris may be chosen as a source of nesting material, evaluation of its presence and contribution to nest building in seabird colonies is important. Here, we determined the contribution of anthropogenic debris to nest construction by a yellow–legged gull Larus michahellis population that largely depends on refuse tips to forage. Two colonies within the southeastern Bay of Biscay, Spain, were sampled in 2019. One of the colonies was in Getaria, where no debris was found in nests, and the second was in Ulia, where 40 % of the nests had some kind of artificial material. In all cases, however, this debris comprised less than 5 % of the nests’ area. Among the studied nests, we found one had a piece of fabric, five had pieces of rope, and 20 had pieces of flexible plastic packaging. These results contrast with other seabird species that face problems of conservation due to the increasing use of plastic for nesting. With the low prevalence of artificial debris (chiefly plastic) in nests found in this study, mortality due to debris entanglement or ingestion is unlikely.

Population change among Pacific, kelp and silver gulls using natural and artificial feeding sites in south-eastern Tasmania

The kelp gull, Larus dominicanus, which is widely distributed around the southern hemisphere, has become established in Australia only in the past half-century. The greatest numbers of kelp gulls in Australia are now found in south-eastern Tasmania in sympatry with the two endemic species, the morphologically similar Pacific gull, L. pacificus, and the smaller silver gull, L. novaehollandiae. We examined populations of the three species in this area. We surveyed large refuse tips and specific shoreline sites in the Hobart area regularly during the winter months in 1981 and again in 1992, recording numbers of each species, and age classes of kelp and Pacific gulls. Between the two survey periods, the number of Pacific gulls and the total number of all gulls present at refuse tips remained unchanged. There was, however, a marked increase in the number of kelp gulls at tips, equivalent to an annual rate of increase of 22.8%, and a corresponding decrease in the number of silver gulls. Kelp gulls of all ages were over-represented at refuse tips, while adult Pacific gulls fed preferentially at more natural shoreline sites. At shoreline sites, adult Pacific gulls appeared to exclude kelp gulls from small bays in 1981, but kelp gulls were present in most of these bays eleven years later. Reducing access to food at refuse tips may be an effective means of controlling the kelp gull population in this area.

Occurrence of oocysts ofCryptosporidiumsp. inLarusspp. gulls

SUMMARYBetween November 1990 and February 1991 101 gull faecal samples, collected in central Scotland, and 50 cloacal lavages, from gulls captured at two refuse tips near Durham, England were examined for the presence ofCryptosporidiumsp. oocysts. Five of 101 (c 5%) of faecal samples and 11 of 50 (22%) of cloacal lavages contained oocysts, of which 64% and 83%, respectively were considered viable when examined with propidium iodide and 4′-6-diamidino-2-phenylindole. Since there is insufficient evidence to ascribe these oocysts to a recognized species they are therefore referred to asCryptosporidiumsp. oocysts. There were significant differences in the occurrence of oocysts between gulls captured at the different refuse tips (P < 0.01), but no significant difference between the distribution of oocysts in two species of gull,Larus argentatus(Herring Gull) andL. ridibundus(Black-head Gull). The differences may be explained by different food sources and feeding habits. The contribution of gulls to environmental contamination withCryptosporidiumsp. oocysts is probably generally small, but may be more significant when large numbers roost on surface waters.

Dynamics of weed populations in a northern subarctic community

The introduced flora of Churchill, northern Manitoba, was studied to draw some conclusions about the dynamics of weeds in northern subarctic communities in general. One hundred and six introduced species have been recorded at Churchill. Fifty-five percent of these were "temporary," dying out when original colonizers senesced (e.g., Avena spp., Setaria viridis). Seventeen percent were "established," i.e., able to set viable seed and maintain their populations (e.g., Thlaspi arvense, Crepis tectorum). Twenty-eight percent "persisted" locally by vegetative propagation or repeated seed input (e.g., Linaria vulgaris, Chenopodium album s.l.). The findings were compared with those of an earlier study. The number of species and their local distributions around Churchill have increased in the last 30 years. This may be due to an increase and diversification in the traffic with southern regions or to an amelioration in the climate. Although one in five species in the vicinity of Churchill are introduced, usually fewer than 12 weed species were established at any one site. Abandoned sites exhibited a rapid disappearance of weeds. Depauperate individuals of a few species were found away from inhabited areas, with none occurring in natural communities. Organic material in refuse tips provided a mild environment with a long growing season. Refuse tips may act as refuges for weeds and as potential sources of their seeds. Aliens that were successful at seed production were either perennials, winter annuals, or biennials. These plants flowered early and hence are able to ripen their seeds. Years with long growing seasons may allow seed production in otherwise temporary species. Dynamics of weedy species around Churchill will likely reflect current and (or) future events in other, more isolated northern communities. Key words: subarctic, weeds, introduced plants.

Feeding Strategies of Male and Female Adult Herring Gulls (Larus Argentatus)

This paper examines the foraging behaviour of adult male and female herring gulls at refuse tips during winter. Although the majority of herring gulls were either on the tip or nearby for much of the daylight period, an individual male or female fed at the tip for only 30 minutes per day. Three types of feeding were distinguished: (a) undisturbed primary feeding on freshly dumped refuse; (b) disturbed primary feeding where the gulls fed whilst a bulldozer was moving the refuse; and (c) secondary feeding on dispersed refuse partially covered with earth. During primary feeding the herring gulls fed at high density and the feeding flock comprised 73% adults whilst during secondary feeding they were at low density and the flock contained only 25 % adults. A comparison of disturbed and undisturbed primary feeding showed that the birds dipped for food from the air in the former but searched for food on the ground in the latter. This resulted in eight times more encounters per individual and much greater competition in undisturbed feeding. Proportionally more adult male than female herring gulls participated in undisturbed (i.e. competitive) feeding, whereas the reverse was true of disturbed feeding. These differences were greatest in the first half of the winter (i.e. October-mid-December). There were no differences in the sex-ratio of those participating in secondary feeding. During undisturbed primary feeding adult females had higher pecking and walking rates and lower encounter rates than males. Males obtained at least a fifth of their food by attacking and displacing other feeding herring gulls, three times more than females. Female herring gulls fed more often on the edge of the refuse pile where competitive interactions were less frequent but also where foraging success was lower. As the undisturbed feeding bout progressed, attack rates of males increased and their swallowing rate was sustained. In contrast, the attack rates of females decreased as did the swallowing rates. The proportion of females present also decreased, suggesting that some females were responding to the increased levels of aggression by leaving the feeding area. Refuse tips provide a variety of feeding opportunities. In a competitive feeding situation the smaller female herring gulls are disadvantaged by the dominance of males. In disturbed feeding they are able to compensate to some extent because their smaller size results in greater manoeuvrability.

qlqlt' tubkinnu, Refuse Tips and Treasure Trove

The Tell Fekherye inscriptions contained more than one surprise for both the Assyriologist and the Aramaist. In this article we will deal with Aramaic qlqlt' which was previously known from texts in various Aramaic dialects from the first millennium C.E. and also with tubkinnu its equivalent in the Akkadian text. Richard Barnett, to whom this article is dedicated, has opened one of the great treasure troves to the scholarly world – the Western Asiatic collections of the British Museum. We take this occasion to also comment on treasure trove in the ancient world.The word qlqlt' occurs in the Tell Fekherye inscription in 1. 22 of the Aramaic text: wmn qlqlt' llqṭw 'nšwh š‘rn klw “may his people scavenge barley to eat from the rubbish dump(s)”. The noun qlqlt' in this form occurs in various Targumic texts. Thus in 1 Sam 2:8 (= Ps 113:7) mē'ašpōt yārīm 'ebyōn “He lifts up the needy from the refuse heap” is translated miqqilqilātā/mĕrīm/yerīm hĕšīkā. The ša‘ar ha-ḥarsīt of Jer. 19:2 is translated tĕra‘ qilqiltā “dung gate” and the enigmatic śēfātayim of Ps 68:14 was interpreted as a plural of 'ašpā “dung heap, refuse dump” and translated qilqilātā. The same translation was offered for 'ašpātōt of Lam 4:5.