No description available.

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No description available.

No description available.

No description available.

No description available.

No description available.

This study investigated the impact of kleptoparasitism and predation by large gulls (Larus spp.) on the recruitment rate, foraging economics and reproductive performance of Atlantic puffins Fratercula arctica breeding on the Isle of May, Firth of Forth, southeast Scotland. The implications of the findings for nature reserve management strategies are discussed. During the period from 1972 to 1989 the population of herring L. argentatus and lesser black-backed gulls L. fuscus nesting on the island was reduced as part of a gull control programme. Since 1989, gull management has involved maintaining gull-free areas by repeated removal of nests. Analysis of data collected over a 23 year period showed that the recruitment rate of puffins to the colony was significantly higher in the areas of the island where gull nest density was low. This suggests that, by reducing the density and spatial distribution of nesting gulls, the control programme successfully increased the attractiveness of the colony as a potential breeding site for puffins. Maintaining gull-free areas was also effective in reducing the frequency with which puffins were attacked by gulls. Kleptoparasitism risk during the morning and evening peaks of puffin feeding activity was 37% in gull-occupied habitat compared to only 5% in gull-free areas. These results indicate that gulls predominantly attacked puffins that bred in close proximity to them and did not move outwith the main gull breeding areas to attack puffins elsewhere on the island. The presence of gulls also significantly reduced the actual rate at which adult puffins attempted to deliver food to their chicks. The lower provisioning rate coupled with the higher kleptoparasitism risk resulted in puffins breeding in gull-occupied habitat delivering 44% fewer food loads to their chicks in the morning and 25% fewer in the evening compared to puffins breeding in gull-free areas. However, despite this difference, there was no evidence of a significant reduction in the growth of puffin chicks or their survival to fledging.

The ring dove (Streptopeliafi sotia) has proved an excellent animal model for studies in reproductive endocrine-behaviour interactions for many years. It shows bi-parental care and has a stereotyped breeding cycle. Androgen receptor and progesterone receptor immunoreactivity (AR-ir and PR-ir) were localised in the brain of male and female ring doves. Nuclear AR-ir in courting birds was widespread throughout the telencephalong diencephalon, and mesencephalon. Nuclear PR-ir was only localised in discrete regions of the preoptic-hypothalamus of both sexes. In the anterior and posterior hypothalamus, high density of AR-ir and PR-ir neurones was concentrated and co-localised in the nucleus preopticus anterior (POA), nucleus preopticus mediahs (POM), nucleus medialis, pars medianis (POMm), nucleus preopticus paraventricularis magnocellularis (PPM), nucleus hypothalami laterahs posterioris (PLH), and tuberal. hypothalamus (Tu). Investigation of the effects of the breeding cycle on anterior pituitary gland and hypothalamic AR-ir and PR-ir showed a significant (p<0.001) increase in AR-ir cells in courting birds when compared with birds at other stages of the breeding cycle. AR-ir cells in birds brooding young was significantly reduced or absent altogether. In the anterior pituitary gland of both sexes, PR-ir cells increased during courtship and significantly decreased in brooding birds. In the anterior hypothalamus of both sexes, no significant change in PR-ir density was observed. However, a significant increase (p<0.05) of PR-ir neurones was seen 'in the ventral and lateral Tu of incubating male and female doves, respectively, whilst a significant decrease in PR-ir neurones was seen in the ventral region of the Tu in birds brooding young (p<0.001). Although no sex difference was obtained in the number of AR-ir neurones, significantly higher staining intensity for AR-ir was measured in male than female doves, in all hypothalamic regions investigated. Similarly, increased PR-ir staining intensity was measured in courting birds than in birds at other breeding stages. In the anterior pituitary gland and all regions of the hypothalamus the percentage co locahsation between AR-ir and PR-ir changes With breeding cycle. The highest percentage of PR-ir and AR-ir co-localisation (70-909/6w) as obtained in courting birds and the lowest (0.27-24%) in birds brooding young. The association between steroid receptor expression and aromatase P450 enzyme(P450AROM)activity in the brain of the ring dove was also investigated. Sexually experienced ring doves were injected intramuscularly with the aromatase inhibitor fadrozole (0.2 ml of 1 mg n-A-') and paired with saline injected controls in a cage containing a nest bowl and nesting material. The fadrozole/ saline vehicle was administered for 3 days at 12-hour intervals. Saline injected control males displayed aggressive and nest-orientated behaviours whereas fadrozole treated males showed none of these behaviours. Similarly, saline injected control females displayed nest-onented behaviours and were sitting on the nest by day 2, whereas fadrozole injected females showed none of these behaviours. On day 4 of courtship, birds were perfuse-fixed and the brains and anterior pituitary glands subjected to immunocytochernistry for androgen receptor (AR), progesterone receptor (PR) and aromatase (P450ARONýIn* saline treated birds of both sexes, nuclear AR-ir and PR-ir were seen in the PON, PPM, POM, POMm, PLH and Tu. In contrast, fadrozole treatment in both sexes resulted in the complete absence of detectable nuclear AR-ir expression, together with a significant decline in the expression of PR-ir in the POM and POMm, and all regions of the Tu (p< 0.001). A sex difference in PR-ir expression was seen in the POA and PPM (p<0.001) of fadrozole treated birds. Fadrozole administration caused decrease in the percentage co-localisation of AR-ir and PR-ir in both sexes. A high density of AROMir neurones was observed in the POM and POMm of saline injected males, which was found to co-express PR-ir (99%). The viability of maintaining in vitro brain slice preparations was studied with the aim to identify and confirm neural circuits involving the anterior and posterior hypothalamus in the initiation of sexual and parental behaviours in this species. Sections were pressure injected with fluorogold (FG) or Dil (8 -15 nl) in the POA, POM, and the ventral, lateral and dorsal regions of the Tu. Results obtained confirm previous reports of neural connections between the Tu and POA. Neural connections were also seen between the Tu and the nucleus medialis hypothalan-ii posterioris (PMH), and several other regions of the mesencephalon and telencephalon, including the nucleus intercollicularis JCo), nucleus ovoidalis (Ov), dorsolateralis posterior thalami (DLP), archistriatum, pars ventrale (Av) and archistriatum, pars dorsalis (Ad). It is concluded that in the dove, central AR-ir and PR-ir expression and co-localisation are closely associated with the sexual stages of the reproductive cycle. Increases 'in AR-ir neurones in the preoptic-hypothalamus in courting birds are consistent with the behavioural role of androgen acting in this brain area during this time. Similarly, the high PR-ir neurones in the preoptic-hypothalamus are consistent with the progesterone-induced initiation of incubation in this species. The high percentage of AR-ir and PR-ir colocalisation in the preoptic-hypothalamus of courting doves supports previous reports involving progesterone acting in these brain regions to terminate the androgen-dependent aggressive courtship behaviour in male doves. The decrease in the number of co-localised AR-ir and PR-ir neurones M the preoptic-hypothalamus following oestrogen synthesis inhibition suggests a role for oestrogen in the progesterone-dependent termination of aggressive courtship display in males, and models proposing a mechanism involving oestrogen in the orchestration of central systems associated with courtship behaviour in the ring dove are presented. Neural connections between the POA and Tu, and Tu with the PMH, ICo, Ov, DLP, Av and Ad may represent the neuroanatomical pathways involved in the integration of courtship display, vocalisation (nest-coos and/or bow-coos), auditory, propriosceptive signals and gonadotropM secretion in the reproductive cycle of the ring dove. These results are consistent with the hypothesis that the POA, Tu and the midhypothalamus are involved in the orchestration of sexual and parental behaviour of the ring dove.

Seabird breeding success and population size on many oceanic islands have declined in recent years as a result of predation by non-native mammals. On Ascension Island, South Atlantic the sooty tern Onychoprion fuscatus breeding population declined precipitously in size in the 1970s. Despite cat eradication in 2003 and a cull of predatory mynas, the tern population between 1990 and 2012 consistently contained 350,000 birds. Shortages of small fish within foraging range of Ascension driven to the sea surface by once more prevalent tuna rather than cat predation probably caused the 1970s decline. Abundance and size of rats increased in response to cat eradication with the impact of rats on the size of the seabird population similar to the combined impact of both cats and rats. Ascension sooty terns have adopted a life-history strategy of sub-annual breeding as a viable alternative to seasonal breeding. The population consistently bred every 289 days, as did most individual birds. Despite an increase in lifetime reproductive rate resulting from sub-annual breeding, I predict a slow but sure decline in the population size unless rats are controlled. Studies of sooty tern migratory ecology are required and the species’ current IUCN Red List category should be reviewed.