Plasticity of Noddy Parents and Offspring to Sea-Surface Temperature Anomalies

Abstract

Behavioral and/or developmental plasticity is crucial for resisting the impacts of environmental stressors. We investigated the plasticity of adult foraging behavior and chick development in an offshore foraging seabird, the black noddy (Anous minutus), during two breeding seasons. The first season had anomalously high sea-surface temperatures and ‘low’ prey availability, while the second was a season of below average sea-surface temperatures and ‘normal’ food availability. During the second season, supplementary feeding of chicks was used to manipulate offspring nutritional status in order to mimic conditions of high prey availability. When sea-surface temperatures were hotter than average, provisioning rates were significantly and negatively impacted at the day-to-day scale. Adults fed chicks during this low-food season smaller meals but at the same rate as chicks in the unfed treatment the following season. Supplementary feeding of chicks during the second season also resulted in delivery of smaller meals by adults, but did not influence feeding rate. Chick begging and parental responses to cessation of food supplementation suggested smaller meals fed to artificially supplemented chicks resulted from a decrease in chick demands associated with satiation, rather than adult behavioral responses to chick condition. During periods of low prey abundance, chicks maintained structural growth while sacrificing body condition and were unable to take advantage of periods of high prey abundance by increasing growth rates. These results suggest that this species expresses limited plasticity in provisioning behavior and offspring development. Consequently, responses to future changes in sea-surface temperature and other environmental variation may be limited.

Reproductive parameters of tropical lesser noddies respond to local variations in oceanographic conditions and weather

“…Dunn, 1975;Ricklefs et al, 1984;Ritz et al, 2005). In the tropical Pacific Ocean, recent studies of sooty terns Sterna fuscata, black noddies Anous minutus and blue-footed boobies Sula nebouxii found a negative impact of SST on the foraging success of adults (Erwin and Congdon, 2007), chick provisioning rates (Devney et al, 2010) and growth (Ancona et al, 2011). Similarly, our findings suggest that lesser noddy chick growth is a sensitive indicator of oceanographic conditions recorded at a fine temporal scale (i.e.…”

“…Few studies, however, have examined the differential response of seabird reproductive performance to fluctuations in oceanic productivity measured within multiple time frames, including both inter-annual and short-term temporal scales (i.e. on a seasonal, weekly and daily basis; but see Erwin and Congdon, 2007;Devney et al, 2010). Understanding the response of seabird populations to environmental fluctuations measured at various spatial and temporal scales is nevertheless crucial to fully evaluate their potential as biological indicators and to address conservation issues (Piatt et al, 2007 and references therein).…”

Divergence in chick developmental patterns among wedge-tailed shearwater populations

“…Locationspecific climate and oceanic variation, both within and among breeding seasons, further influence patterns of local resource availability (Smithers et al 2003, Devney et al 2010. As a result, food availability can vary considerably among breeding colonies throughout a species range (Weimerskirch et al 2005a), particularly among colonies in different habitats.…”

“…Differing developmental responses to variation in food supply have been seen in food manipulation experiments in seabirds. Some species display a facultative ability to adjust to changes in food intake by varying allocation to a range of growth parameters (Congdon 1990, Kitaysky 1999, while others de monstrate little ability to adapt to food reductions (Devney et al 2010). Comparisons among foraging guilds demonstrate the potential for seabird developmental patterns to be evolved responses to variation in resource availability.…”

Ecological effects of climate change on little penguins Eudyptula minor and the potential economic impact on tourism

“…Warmer SSTs, asso ciated with the El Niño Southern Oscillation (ENSO), have also been associated with reductions in seabird populations on the Great Barrier Reef (Heatwole et al 1996, Batianoff & Cornelius 2005. Increased SSTs are believed to reduce prey availability to seabirds through decreased productivity at lower trophic levels and/or movement of forage fish or subsurface predators, either horizontally or vertical ly (Peck et al 2004, Erwin & Congdon 2007, Devney et al 2010. Strong winds and severe storms also affect seabird breeding participation, success of breeding and mortality (King et al 1992, Garnett et al 2010.…”