Atlantic Puffin Fratercula arctica

Status;  International importance;  Population estimates;  Distribution;  Annual abundance/ productivity; Phenology/diet/survival

Description

The following was adapted from original text by Mike P. Harris and Sarah Wanless in Seabird Populations of Britain and Ireland (with permission from A&C Black, London).

The Atlantic puffin is the most instantly recognisable and popular of all North Atlantic seabirds. It breeds in the North Atlantic and the adjacent Arctic Ocean, with strongholds in Iceland and Norway, with around 10% of the population breeding around the British Isles, where it is the second most abundant breeding seabird. Atlantic puffins are pelagic and we are still largely ignorant of where they spend their time away from the colony. Those from north western Britain disperse widely outside the breeding season, as far as Newfoundland in the west and the Canary Islands to the south and even into the Mediterranean as far east as Italy. In contrast, most of those from colonies in eastern Britain remain within the North Sea though in recent decades some have dispersed as far as the Bay of Biscay.

Atlantic puffins typically nest underground in burrows dug in the soil of offshore islands, but where such habitat is sparse they nest among boulder screes or at low densities in cracks in sheer cliffs. The species is highly colonial and most colonies occur where the nesting birds are safe from mammalian predators. However, during the breeding season a colony can appear deserted during the middle of the day since most birds are either down burrows or out at sea feeding. At other times awe-inspiring numbers can be seen standing on the slopes, bobbing around on the sea or flying in vast wheels over the colony. Chicks are fed on small fish that the adult carries cross-wise in its beak. In the UK the commonest prey is the lesser sandeel, followed by sprat, herring and a wide range of small juvenile gadoid fish. Fish are caught by underwater pursuit, usually several at a time.

Conservation status

Atlantic puffin is currently identified as a conservation priority in the following:

Amber listed in Birds of Conservation Concern 3 (2009 update)

(further information on Conservation Designations for UK Taxa)

Amber listed in Birds of Conservation Concern in Ireland 2 (2007 update)

International importance

*AOB = Apparently Occupied Burrows

The UK population figure (rounded to the nearest hundred) was derived from data in Mitchell, P.I., Newton, S.F., Ratcliffe, N. and Dunn, T.E. (eds.) 2004. Seabird Populations of Britain and Ireland. Poyser, London. This was also the source of figures for the Biogeographic and World populations.

UK population estimates and change 1969-2002  (census data)

During Seabird 2000 and the SCR Census surveyors were able to count apparently occupied burrows (AOB) at most colonies. Here the main source of error is the misclassification or overlooking of burrows. However, for logistical reasons complete coverage is impossible to achieve at many colonies. In such situations the density of burrows must be determined in sample plots, the area of the colony estimated and the measures combined to get an estimated population size. Where birds nest under boulders, in mixed colonies with Manx shearwaters, in completely inaccessible places or at low densities along stretches of cliffs (mainland colonies), counts of burrows are impractical. In these cases surveyors must count individual birds attending the colony. Such counts can be highly variable both within and between days, and the lack of any obvious factor influencing attendance, means that such counts are of rather limited value in assessing breeding numbers, but they do at least give some idea of colony size. April and May are the prime months for counting individual birds before substantial numbers of immatures begin to attend colonies.

For the calculation of total populations, some arbitrary decisions had to be made to allow the combination of counts of individuals and AOBs. The practice of assuming that one individual corresponded to one AOB was applied to counts from all three national censuses. This approximation may well result in a serious underestimate of the number of AOBs. However, the overall estimates of the SCR Census and Seabird 2000 should be broadly comparable. In both surveys 83% of the total population estimates came from counts or estimates of AOBs. Furthermore, in the SCR Census 65% of the counts of individual birds came from the preferred counting months compared to 73% during Seabird 2000.

*AOB = Apparently Occupied Burrows

For census results for individual countries and Ireland, the Channel Islands and the Isle of Man see under relevant sections below.

Distribution/abundance

The Seabird 2000 census provides the most comprehensive recent assessment of the distribution and abundance of breeding seabirds. Numbers of Atlantic puffin found in different regions, and a map showing where colonies are found and how large they are is provided in the Seabird 2000 Atlantic puffin results page (PDF, 2.0 mb).

Annual abundance and productivity by geographical area

UK phenology, diet, survival rates

Phenology

No systematic data on phenology (timing of life-cycle events) have been collected as part of the SMP.

Diet

Our understanding of puffin diet comes from data collected at a few geographically dispersed key sites. Because diet is likely to vary from site to site, and given few sites are monitored , caution should used in drawing wider geographical conclusions from these data.

Sandeels (Ammodytes spp.), an energy-rich shoaling fish, comprise a large proportion of the diet of puffins at two sites where diet is studied. The proportion of sandeels fluctuated; at Fair Isle in Shetland (Figure 4) it declined over the monitoring period (especially the 'large' sizeclass), though on the Isle of May in SE Scotland (Figure 3) there was no clear trend. However, the size and energy content of sandeels caught by and available to puffins on the Isle of May declined over the period 1973-2002¹, and in some years (such as 2004) the energy content of sandeels was found to be far lower than would be expected for their size and coincided with very poor breeding success for puffins and other sandeel-feeders². The mean mass of food loads of puffins breeding at Fair Isle declined from the mid 1990s (Figure 5) and may have contributed to low breeding success during those years. The causes for the change in the size of sandeels around the Isle of May are probably due to climate change rather than from the effects of fishing.

Between 2004 and 2008, snake pipefish Entelurus aequoreus appeared in the diets of many seabirds around the UK³ -including puffins during 2006-2007. The energy content of this bony fish, which before the early 2000s was very rare in UK waters, is very low⁴. Snake pipefish, therefore did not provide an alternative energy source during a time when puffin's usual prey species (sandeels and sprats) were scare. Indeed, pipefish can choke chicks when fed to them in quantity. The reason for the appearance of snake pipefish is uncertain, but is not thought to be related to climate change.

Figure 3. Percentage of sandeels (by weight) in the diet of young puffins at the Isle of May (SE Scotland), 1987-2010.

Figure 4. Composition of fish loads brought to puffin chicks at Fair Isle (Shetland) 1986-2010.

Figure 5. Mean mass (g) of fish loads brought to puffin chicks at Fair Isle (Shetland), 1986-2010.

Return rates and survival rates

Important notes on interpretation: Estimation of Atlantic puffin adult return rate and survival rate is currently only undertaken at two sites within the Seabird Monitoring Programme -The Isle of May in the Firth of Forth, SE Scotland and Skomer Island, Pembrokeshire, SW Wales. Return rates are based on sightings of individually colour-ringed birds and are calculated as the proportion of marked birds present in year one that is seen in the following year. Because not every adult alive is seen each year, return rates for 2010 presented here for Isle of May need to be treated as minimum estimates of survival of birds seen in 2009. In contrast, survival estimates - as presented here for Skomer - do take into account birds that are not seen one year but which re-appear in following years.

Return rate of Atlantic puffins breeding on the Isle of May (Figure 6) has shown no consistent trend, though declined between the mid 1990s and the mid 2000s; however, it fell to extremely low levels in 2007 and 2008, which was the likely cause of a population decline on the island noted between 2003 and 2008. Atlantic puffins breeding on Skomer (Figure 7) show a significant downward trend in survival, but without the sharp declines in 2007 and 2008 that were seen on the Isle of May. Little is currently known of the causes of changes in survival rates of puffins, though recent evidence suggests a shift in overwintering range of Isle of May breeders from the North Seas into the east Atlantic, possibly reflecting deteriorating conditions in the North Sea⁵.

Figure 6. Annual return rate of Atlantic puffin breeding on the Isle of May (SE Scotland), 1987-2010.

Figure 7. Annual survival rate of Atlantic puffin breeding on Skomer (SW Wales), 1987-2009.

References