Demographic parameters of black-browed albatrosses Thalassarche melanophris from the Falkland Islands

Abstract

Black-browed albatrosses Thalassarche melanophris are currently classified as globally endangered. The most important populations of this species are believed to be declining due to, amongst other factors, unsustainable levels of incidental mortality in fishing gear. However, detailed demographic data are lacking for several critical populations, including the largest of all, nesting in the Falkland Islands. Here, we present data from the first Falkland Islands detailed demographic study (at New Island) and show that, from 2003 to 2009, the mean adult survival probability was 0.942 (95% CI: 0.930-0.952). Nesting frequency of adults is amongst the highest recorded for Thalassarche albatrosses and breeding success (0.564 chicks per egg) is within normal values. The nesting population in the intensively studied plots experienced an increase of 4% per year from 2004 to 2009. These results indicate that the Falklands population may not be as threatened as previously supposed, although studies from more sites and a longer time series are needed to confirm or refute this. The high survival rates may partly reflect recent efforts to mitigate bycatch made by the Falkland Islands and other fisheries in the region. The reinforcement of such initiatives may be critical to buffer the black-browed albatross population against ecosystem shifts and natural disasters (such as harmful algal blooms) that will likely become more frequent with ongoing global changes.

High occurrence of jellyfish predation by black‐browed and Campbell albatross identified by DNA metabarcoding

“…During this study, the breeding success was similarly high at Steeple Jason and New Island in 2015 even though jellyfish occurred more frequently in the diet at Steeple Jason Island. The breeding success was slightly lower at Steeple Jason in 2014, however, was still higher than the long-term average at the Falkland Islands (New Island 56% from 2004 to 2009), and higher than conspecifics at other island groups (ACAP 2010;Catry, Forcada, & Almeida, 2011). This suggests that the consumption of jellyfish by albatross may not be impacting breeding success at the population level.…”

Differences in the timing and extent of annual moult of black-browed albatrosses Thalassarche melanophris living in contrasting environments

“…Other lines of evidence point similarly to the conclusion that black-browed albatrosses nesting in South Georgia face a more challenging environment, not only when breeding, but perhaps throughout the annual cycle. The probability of breeding deferral for experienced individuals is much higher on South Georgia than on the Falklands (Arnold et al 2006;Nevoux et al 2010;Catry et al 2011). Furthermore, breeding success is considerably lower and more variable at South Georgia (Arnold et al 2006;Nevoux et al 2010;Catry et al 2011, own unpubl.…”

“…Birds from the Falklands are relatively sedentary, wintering on the Patagonian shelf and shelf-break (Grémillet et al 2000), while those from South Georgia are long-distance migrants, mostly wintering off southern Africa (Phillips et al 2005). Black-browed albatrosses from the Falklands generally enjoy a higher breeding success and a lower incidence of breeding deferral by experienced breeders (skipping breeding in 1 year) than their counterparts from South Georgia (Arnold et al 2006;Nevoux et al 2010;Catry et al 2011). If this indicates a more benign environment, presumably with greater food availability, we could predict a higher moultbreeding overlap in the Falklands, as in these conditions individual birds would be in a better position to simultaneously invest in offspring and self-maintenance (Alonso et al 2009).…”

Polar marine biology science in Portugal and Spain: Recent advances and future perspectives

“…Chicks at the colony are ringed annually and many have already returned and started breeding. Using these data, the first estimates of survival and breeding success for the Falkland Island breeding albatrosses have been recently published (Catry et al, 2011b). Results were striking, with a high annual adult survival, a low incidence of breeding deferral and good breeding success.…”