Colony attendance and at‐sea distribution of thin‐billed prions during the early breeding season

Abstract

17Procellariiform seabirds have extreme life histories; they are very long-lived, first breed when 18 relatively old, lay single egg clutches, both incubation and chick-rearing are prolonged and chicks 19 exhibit slow growth. The early part of the breeding season is crucial, when pair bonds are re-20 established and partners coordinate their breeding duties, but is a difficult period to study in burrow-21 nesting species. Miniature geolocators (Global Location Sensors or GLS loggers) now offer a way to 22 collect data on burrow attendance, as well as determine at-sea movements. We studied the early 23 breeding season in thin-billed prions Pachyptila belcheri breeding at New Island, Falkland Islands. 24Males and females arrived back at the colony at similar times, with peak arrival in the last days of 25 September. However, males spent more time on land during the pre-laying period, presumably 26 defending and maintaining the burrow and maximising mating opportunities. Males departed later than 27 females, and carried out a significantly shorter pre-laying exodus. Males took on the first long 28 incubation shift, whereas females returned to sea soon after egg laying. During the pre-laying exodus 29 and incubation, males and females travelled at similar speeds (>250km per day) and were widely 30 distributed over large areas of the Patagonian Shelf. Inter-annual differences in oceanographic 31 conditions were stronger during the incubation than during the pre-laying exodus and were matched by 32 stronger differences in distribution. The study thus suggests that extended trips and flexible 33 distribution enable thin-billed prions to meet the high energy demands of egg production and 34 incubation despite low productivity in waters around the colony during the early summer.

Causes and consequences of individual variability and specialization in foraging and migration strategies of seabirds

“…Males (which usually perform a greater role in nest defence) often forage more locally and visit the colony more frequently, whereas females often go on a pre-laying exodus, engaging in longer foraging trips in more productive waters to meet energetic or other nutritional requirements for the clutch (Lewis et al 2002, Yamamoto et al 2011, Hedd et al 2014, Quillfeldt et al 2014, Pistorius et al 2015. Indeed, changing energetic or nutritional requirements during the breeding cycle would explain why sex differences are apparent only at certain stages in mono morphic species such as Barau's petrel Pterodroma baraui (Pinet et al 2012) or why late-incubation trips by male southern rockhopper penguins are longer, as they do all the early chickguarding (Ludynia et al 2013).…”

“…Many species are migratory, making directed movements from breeding to nonbreeding grounds to exploit seasonal peaks in prey abundance or to avoid inclement weather, with implications for survival and subsequent fecundity , Reiertsen et al 2014. The changing degree of central-place constraint during the breeding period -from pre-laying through incubation, brood-guard and later chickrearing (post-guard) -can lead to major shifts in distribution, activity patterns or diet within individuals (Hedd et al 2014, Quillfeldt et al 2014). There may be within-breeding-season (date-related) differences in distribution or diet, which reflect extrinsic changes in the environment ).…”

“…This may reflect habitat specialization or avoidance of competition in sexually dimorphic species and sex role specialization or sex-specific nutrient requirements in monomorphic or dimorphic species (Lewis et al 2002, Phillips et al 2004. Sex differences in distribution and behaviour of seabirds tend to be more apparent during particular periods, for example during pre-laying (presumably related to sex-role partitioning of nest defense), affecting attendance patterns (Hedd et al 2014, Quillfeldt et al 2014. However, such effects are far from universal; despite a degree of spatial segregation, activity patterns of male and female albatrosses are comparable during the breeding and nonbreeding periods, suggesting little difference in prey type or foraging method (Mackley et al 2011, Phalan et al 2007.…”

Escaping the oligotrophic gyre? The year-round movements, foraging behaviour and habitat preferences of Murphy’s petrels

“…longer twilight periods at higher latitudes). Dark ness (night), morning twilight (morning), daylight (day) and evening twilight (evening) were also split into discrete groups based on corresponding light data and are shown as bar plots (right panels) with asterisks denoting significant differences between groups: **p < 0.01; ***p < 0.001 ductive roles in the early breeding season (Hedd et al 2014, Quillfeldt et al 2014. Like Murphy's petrels, Barau's petrels and Chatham petrels Pterodroma axillaris (Rayner et al 2012) show sexual segregation during pre-laying, and the males travel further to more productive areas, suggesting that this behaviour might be common among gadfly petrels.…”

Spatial variation in the benthic community composition of coral reefs in the Wakatobi Marine National Park, Indonesia: updated baselines and limited benthic community shifts

“…We focus on the prions (Pachyptila spp. ), a monophyletic group of pelagic seabirds, whose distribution is exclusive to the Southern Ocean, where they breed on remote oceanic islands during the austral summer (Quillfeldt et al 2014) (fig. 1; supplementary table S1, Supplementary Material online).…”