There are numerous reports in the literature of advancing trends in phenophases of plants, insects and birds attributed to rising temperature resulting from human-driven climate warming. One mechanism that enables a population to respond rapidly to changes in the environment is termed phenotypic plasticity. This plasticity grants a degree of flexibility to enable the timing of developmental stages to coincide with resource availability. If, however, environmental conditions exceed the plastic limits of an organism, evolutionary change may be necessary in order to ensure continued survival of their populations. We review evidence for phenotypic plasticity and genetic adaptation in phenological characteristics associated with climatic warming. We focus this review on examples from trees, insects and birds. We found many reports of direct observations of phenotypic plasticity but fewer studies providing conclusive evidence of genetic adaptation. Evidence for changes in genes linked with adaptive traits associated with a warming climate was stronger in insects, that have a relatively short life-cycle, than in longer-lived birds and trees. Further research is required to identify both appropriate long-term data sets for a range of species and traits and suitable analytical methods, which will permit the study of the complex interaction between phenotypic plasticity and genetic adaptation of organisms and their populations in response to climatic change.

Understanding the departure decisions of migratory birds is critical for determining how changing climatic conditions will influence subsequent arrival times on the breeding grounds. A long‐term dataset (1972–2008) of Whooper Swan Cygnus cygnus departure dates from a wintering site in Ireland was used to assess the factors determining the timing of migration. Early and late migrating swans showed different departure patterns. Earlier wintering ground departure was more pronounced for the first 50% of the population than the last 10% of departing individuals. Earlier departure was associated with an increase in February temperatures at the wintering site for all departure phases except the date when the last individual departed. The date by which the first 50% of Swans had departed was earlier with increasing numbers of wintering Swans, suggesting that competition on the wintering grounds may further influence the timing of departure. The results also suggested that departure is mediated by the influence of spring temperature on food resources, with increased February grass growth in warmer years enabling earlier departure of migrating Swans. To determine why arrival dates in the breeding ground have altered, environmental conditions in the wintering grounds must be taken into account.

SummaryAn effective conservation strategy for a species requires knowledge of its biology and life history. This applies to the endangered Ma’oma’o Gymnomyza samoensis, a honeyeater endemic to the Samoan archipelago. Now locally extinct in American Samoa, this species is currently found only in declining numbers on the islands of Upolu and Savai’i in Samoa. Despite being endangered, the life history and breeding behaviour of the Ma’oma’o has not been documented previously. Here we examine Ma’oma’o nesting and breeding biology, which are unique among studied honeyeaters and unusual for passerines in general. Ma’oma’o lay only a single egg per clutch and have an extended breeding season that occurs outside the rainy season and peaks during budburst. Allometric analysis of the length of the nesting period of different honeyeaters versus adult body weight showed that Ma’oma’o remain in the nest for a longer period than expected for their body size. The post-fledging dependency period of 2.5–3 months was also extended compared to other honeyeater species. No Ma’oma’o were observed re-nesting after successfully raising a chick, though pairs attempted to re-nest following breeding failure. Despite the extended breeding season, the maximum annual reproductive capacity of Ma’oma’o is limited by their one-egg clutch and failure to nest again after fledging one chick. We discuss how these slow life history traits can influence conservation strategies, affect monitoring and limit recovery.

Habitat fragmentation and invasive species are two of the greatest threats to species diversity worldwide. This is particularly relevant for oceanic islands with vulnerable endemics. Here, we examine how habitat fragmentation influences nest predation by Rattus spp. on cup-nesting birds in Samoan forests. We determined models for predicting predation rates by Rattus on artificial nests at two scales: (i) the position of the bird's nest within the landscape (e.g. proximity to mixed crop plantations, distance to forest edge); and (ii) the microhabitat in the immediate vicinity of the nest (e.g. nest height, ground cover, slope). Nest cameras showed only one mammal predator, the black rat (Rattus rattus), predating artificial nests. The optimal model predicting nest predation rates by black rats included a landscape variable, proximity to plantations and a local nest site variable, the percentage of low (<15 cm) ground cover surrounding the nest tree. Predation rates were 22 ± 13% higher for nests in forest edges near mixed crop plantations than in edges without plantations. In contrast, predation rates did not vary significantly between edge habitat where the matrix did not contain plantations, and interior forest sites (>1 km from the edge). As ground cover reduced, nest predation rates increased. Waxtags containing either coconut or peanut butter were used as a second method for assessing nest predation. The rates at which these were chewed followed patterns similar to the predation of the artificial nests. Rural development in Samoa will increase the proportion of forest edge near plantations. Our results suggest that this will increase the proportion of forest birds that experience nest predation from black rats. Further research is required to determine if rat control is needed to maintain even interior forest sites populations of predator-sensitive bird species on South Pacific islands.

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