Gentoos top the penguin charts

Monday, August 31st 2009 - 2:15 am UTC
Gentoos top the penguin charts as seabirds return in record numbers

Gentoo penguins are returning to the Falklands in record numbers, after their best breeding season in more than ten years. Kings, too, continue to thrive, making this season’s Seabird Monitoring Programme one of the healthiest undertaken. Falklands Conservation officer Pierre Pistorius has produced this special report for the Penguin News…

Gentoos have made a remarkable recovery after mass mortality Gentoos have made a remarkable recovery after mass mortality

The Falkland Islands Seabird Monitoring Programme (FISMP) was initiated in 1989/90 with the objective of monitoring gentoo, magellanic, rockhopper and king penguins and black-browed albatross.

This has become the longest running species monitoring programme in the Islands, and is vital to identify the health of the populations and, importantly, it can detect where populations are declining and at risk.

In 2006, annual monitoring of southern giant petrels was incorporated and, during the same year, a long-term demographic study was also initiated on black-browed albatross on Steeple Jason.

Each year Falklands Conservation monitors a number of study colonies around the Islands, and every five years a full island census is conducted.

The monitoring effort is conducted over November to count breeding pairs on nests, and in January/ February to count the number of chicks just before fledging.

The combination of this data allows detection of changes in population size and breeding success.

Gentoo penguins are annually counted at 15 colonies, and during the 2008/09 season showed a remarkable increase of 53.5 per cent from the previous year’s counts.

This represents the highest number of gentoos recorded from and population numbers at present could well be the highest they have been over the past 15 years.

It also represents a full recovery after the mass mortality that was associated with the harmful algal bloom event in 2002/2003.

Despite the fact that mortality in February resulted from starvation and avian pox at some sites, it is estimated that this affected only a small proportion of the population.

These deaths, which are unusual so close to fledging, was in all likelihood related to a warm water anomaly in early February which probably affected their food resources.

Along the east coast of East Falkland the faeces of penguins were noted to have lost the pink colouration resulting from consuming lobster krill.

This may have been the key prey item, known to make up a significant proportion of the diet in gentoos that either shifted distribution or suffered mortality as a result if the influx of warm water.

The outbreak of avian pox was restricted to a few colonies and fortunately there were no observations of it having spread to other species.

Last season’s counts from the six Rockhopper penguin colonies that are annually monitored showed some signs of recovery with a small but encouraging increase in numbers during the past two years.

The island population declined by close on 100,000 pairs between 2000 and 2005, largely as a result of the 2002 algal bloom event, and is currently only about 15 per cent of its former population in the 1930s.

Although rockhopper penguins are potentially being impacted through pollution, predation and disease, food limitation is most certainly the most likely cause for the long term population decline.

Magellanic penguins are monitored at Volunteer Point, Sea Lion Island and Steeple Jason, where the numbers of occupied burrows are counted along transects within the same area each year. The number of magellanics occupying burrows has shown a general decline since 2000, although in the 2008/09 season there was a small increase in numbers from the previous year.

For the third consecutive year breeding success has, however, been above average. The breeding population of magellanics penguins in the Falklands has been estimated at about 100,000 breeding pairs, but the burrow-nesting habits, varying densities within colonies, and extensive distribution makes this the hardest Falklands penguin species to monitor.

The population estimate is consequently very crude and we currently have a relatively poor understanding of the status of the Falklands population.

King penguins at Volunteer Point continue to thrive. A record number of 594 chicks were counted last season. The population has slowly been increasing since the first count in 1980.

This increase in numbers is largely mirrored throughout the sub-Antarctic and represents a recovery after more than a century of decline as a result of their exploitation for penguin oil, associated with the sealing industry.

King penguins breeding on the Falklands had all been exterminated by 1870. It is thought that the recent rapid increase in numbers here could also be attributed to immigration from South Georgia, where numbers have been increasing and the population expanding.

If anyone is interested in being sent the full FISMP 2008/09 Report in PDF, please email info@conservation.org.fk&#<;/a> .

Falklands Conservation would like to thank all the landowners who kindly allowed access to conduct fieldwork on their land, and all individuals involved in volunteering and logistics. FISMP is supported and funded by the Falkland Islands Government through the environmental studies budget. (Penguin News)

Source:
http://en.mercopress.com/2009/08/31/gentoos-top-the-penguin-charts-as-seabirds-return-in-record-numbers