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Andrew Stowe - Watson Project 2006-2007
Life on the Wing: Traveling Pole to Pole with the Arctic Tern
Quarterly Report 1
June 6 - Sept 10, 2006
First World Breeding Grounds:
Canada, Scotland, England
Ecology and Biology
Churchill, Manitoba, Canada (June 6 - July 10)
The Arctic Terns arrived in the tundra of Churchill and the Hudson Bay region in the last week of May and the first week of June, 2006. The Churchill Northern Studies Center provided an ideal base to conduct work, with a large body of scientists available to provide insight into all aspects of the local area. The majority of the area's Arctic Tern population returned May 30-June 2, about 1 week prior to my arrival to this northern outpost. Seven major Arctic Tern colonies persist in the area and are spread out from a western site located in the town itself close to the mouth of the Churchill River, to an inland site on a small island in a lake accessible by hunting/logging roads approximately 30 kilometers (approximately 18 miles) east of the town. These colonies have been relatively stable with respect to location for at least the last 30 years (Dr. Robert Alison, pers com).
During the first week of my stay, Arctic Terns were observed engaging in courtship display, and early breeders may have began laying eggs at this time as well. The courtship, called Fish Flight, proceeded in the following manner: the male presented the female with a gift (usually a small fish). If the female accepted the offering, both the male and female tilted their heads back, bills pointing straight up, and either copulation ensued or the female ate the fish but would not copulate, waiting for additional gifts to be delivered. Occasionally the female rejected the gift outright, leaving the male to either present it to a different female or to attempt to secure a new gift. During copulation, the male stood on the back of the female and mating lasted between 1 and 5 seconds. Males were observed making several attempts at copulation with a single female over a relatively short period of time.
Nesting habitat in the seven colonies consisted of small grassy islands in ponds, sandy spits, dry mud flats, gravel pits, and open sand beaches. The first nests with eggs were detected on June 15, 2006. Two nests, each containing two eggs, were being incubated on this date by the parents in a sandy gravel pit. At one point on this day, I observed an adult tern bringing a fish to a second adult incubating at one of the nest sites. The incubating parent accepted the fish and after eating it, flew towards the fishing ground and the first adult took over the role of incubation. Shared parental care among Arctic Terns has been observed by other researchers as well. Eggs in all nest habitats are laid in small scrapes or directly on the ground. Nests with eggs were subsequently observed in all colonies within a period of 2-3 days following the detection of the first eggs on June 15. This might suggest that colonies are not distinct and separate, but that exchange of individuals occurs among colonies. Arctic Terns are capable of flying up to 10 miles to obtain food, so it is not inconceivable that terns could fly between colonies. Predators of both eggs and young birds in the Churchill region included Herring Gulls, Parasitic Jaegers (Arctic Skuas), and Common Ravens.
By June 22, defensive behavior (dive bombing) at all colonies was notably more aggressive, with birds striking the head or hat brim (or highest point like a raised stick) of observers directly with their bills. On June 24 and 26, 25 and 13 eggs were counted at two colonies respectively. Determining an accurate total of eggs at other colonies was prevented by difficulty of access to certain areas, like small islands in the middle of large lakes. One such island colony, however, was reached on July 3 when a canoe was secured, at which time 5 chicks (hatchlings) and 21 eggs were detected. This date was the first in which chicks were detected in colonies, with 2 detected at a second colony on the same day. One of these chicks was observed in the process of hatching and the remainder of the chicks found on this date had most likely hatched within the last 24 hours (ie were downy and somewhat mobile).
Over the course of my stay, the number of breeding terns present at each colony (counted on a regular basis) remained stable. Between 200 and 300 pairs of Arctic Terns total bred in the Churchill region over all 7 colonies in 2006. Minor variations in colony counts during 2006 were most likely the result of variations in the number of birds away from the colony (foraging in the bay) during the time of counting. This total is comparative to that of previous years, but recently the differences between average, above average, and below average years have been growing (Dr. Alison, pers com).
When I left the Churchill region on June 6, most eggs had hatched and the fledglings had grown substantially, though they had not yet entered the juvenile stage.
Musgrave Harbour-Lumsden-Hare Bay, Newfoundland, Canada (July 11 - July 26)
I arrived in the northeast coast of Newfoundland several days after reaching the province. While Arctic Terns had nested directly on the sand beaches in previous years (prior to declines in cod fishing), their colonies were now only found on offshore islands (Wadham, Penguin, and Cabot Islands). A spotting scope allowed terns to be observed from certain coastal areas and from the wharf and harbour, but accurate counts of individuals and nests was difficult at best. On the first day I spent in Musgrave Harbour, I arranged a boat trip to the islands with a local fisherman, Beaton Abbott, in whose house I was staying, but on each day the trip was postponed because of bad weather and rough seas, and thus the islands were never reached. Beaton ensured me that after my departure, he and his grandsons would make a trip to the islands on the first day that weather allowed and would provide me with data on the tern abundance and distribution there.
South of Musgrave Harbour, near the town of Lumsden, a small colony of Arctic Terns was detected on July 15 on the sand flats and beaches of the protected Deadman's Bay. 23 terns were present in this area, 13 of which were juveniles that did not show adult plumage. Later in the day on this date a second fisherman, Curtis West, agreed to take me in his lobster boat to the Southern Cat Island off the coast of Lumsden, where terns had been reported in the past. On the sand beach of the north end of the island, a large colony of approximately 150 terns was present, again with a large percentage of juveniles in non-adult plumage.
The largest colonies of Arctic Terns in Newfoundland were reported to be at Hare Bay, but upon arriving to Hare Bay, south of Lumsden, it became clear that there were actually at least 2 Hare Bays (of the exact same name) in Newfoundland. There were no tern colonies at Hare Bay south of Lumsden, and I presume that the second Hare Bay in northwestern Newfoundland is home to the large tern colonies reported in the liturature. The reports that Arctic Terns were breeding near the towns of Branch and New Bridge were also not confirmed, as no colonies could be detected in these areas. It is not likely that the terns would have begun migrating east south-east as early as mid-July. It is more likely that tern colonies were not established (or were not successful) in these areas in 2006.
Fair Isle, Shetland Islands, Scotland (July 29 - August 10)
Fair Isle, two and a half hours by ferry south of the main Shetland Isles, was reached on July 29. The Fair Isle Bird Observatory provided an ideal base to conduct work, with the staff present available to provide insight into many aspects of the local area. Of the 800 Arctic Tern colonies in Britain, 500 are located in the Shetland Islands (Tipling, David, Where to Watch Birds in Britain and Ireland, 2005), several of which are located on the small (3 miles by 1.5 miles) Fair Isle. Arctic Tern ringing (banding) on Fair Isle is conducted early in the breeding season when the chicks first hatch. My arrival coincided with the termination of the tern's breeding season and the initial stages of their departure. I was also able to observer the first wave of Arctic Terns passing through on migration from farther north. Of all the young terns observed on Fair Isle, less then 5 had yet to fledge. Most of the young observed had probably fledged between 1 and 3 weeks prior to my arrival. Estimating tern abundance at all colonies over the time of my stay allowed a partial understanding of the rate of emigration of Arctic Terns (juveniles and adults) from the area.
On July 29 the largest colony (in an area called Buness), where tern breeding most likely began slightly later in the season than at other colonies, had 150-200 individuals, including juveniles that had fledged fairly recently and still displayed brown coloration of the wing and back feathers. By August 10, 60-70 Terns continued to occupy this site, while the other colonies had either completely or mostly disbanded by this time. The drop in abundance over this 2 week period was relatively abrupt, with 115-145 observed on August 3, 110-130 on August 8, and finally the low abundance of 60-70 on August 10. This final observation however may have been heavily affected by high winds and rain on that day that potentially forced the terns into places of greater cover and lower visibility.
The second largest colony was centrally located on Fair Isle near an area called Pund. Over the period July 31 to August 10, this colony decreased from 90-100 individuals first to 50-60 (20% juveniles, approximately 5 fledglings on the ground, and 6 dead fledglings not counted), then to 45-55 (14 dead fledglings also observed, not counted), then to 31-40, and finally to 20 (with a large proportion fledgling or juvenile). This data could be transformed and represented graphically and may be presented in such a format at a later date.
At the time of my arrival, three of the other colonies on the island had begun disbanding already, with only 10-15 remaining at one of the colonies, and 15-20 individuals at the other two. By August 4, these smaller colonies had completely disbanded, with all individuals dead or departed and no Arctic Terns observed.
In the protected harbour waters on the northeast side of the island on July 30, a group of 110-130 Arctic Terns were feeding noisily and aggressively around the dock and the wharf on what were probably juvenile pollock and lumpsuckers. Several individuals within the group of terns were observed flying back and forth in the direction of the Buness Colony, which is in direct proximity with the harbour. Based on the nature of their feeding behavior, a large proportion of this group of terns in the harbour were most likely individuals migrating together from colonies farther north on the main Shetland Island. Similar groups of terns were observed each evening at approximately the same time until August 8, with feeding groups deceasing in size from 110-130 first to 80-110 (10-20% juv/non-breeding), then to 65-75, and finally to 10-15 over this 9 day period. This last relatively small group was most likely comprised mainly of individuals from the Buness Colony, and represents the termination of the first major migratory wave from colonies farther north.
Forres-Findhorn-Spey-Rattray, north-northeast coast Aberdeenshire, Scotland (August 15 - August 18)
In terms of Arctic Tern migration, I should have departed from the Fair Isle and the Shetlands early in the first week of August (August 3-5) when the large wave of Arctic Terns appeared to be passing through the area. I remained on Fair Isle until August 10 with the impression that the initial large wave of Terns would persist (or that a second wave would move through), and because foul weather prevented the ferry from leaving on August 7 as originally scheduled. Thus when I arrived on August 15 (5 day gap a product of transport time) at the Culbin bar and mud flats near Forres and Inverness with the plan to travel along the northeast coast of Scotland, past Aberdeen and down to Edinburgh, most of the Arctic Terns had already moved through the area. Culbin bar was occupied by a large number of gulls and 3 Sandwich Terns.
Later on August 15 in Findhorn Bay, east of Culbin, there were no Arctic Terns on the flats near the Carse airfield taxiway (opposite Cullerne Farm), but several were still resting in a mixed flock of terns on The Spit, near the harbour and the river mouth. Here a group of 45 terns was comprised of 7 Arctics, 30 Sandwiches, and 8 Commons. Continuing east along the coast to Hopeman Harbour, Lossiemouth Harbour, and the Spey Bay and River, I encountered only Common and Sandwich Terns. The following day, on August 16, I arrived at Rattray Head, the most northeast point in Aberdeenshire and a geographically ideal place to observe migrants. On this and 3 subsequent days, groups of terns were observed continuously moving east and south. Half-hour counts produced an average of 15 and 9 Arctic Terns on August 15 and 16, respectively. The Arctic Terns observed at this time often passed in long, spread-out single-file lines. Single bird occasionally dove for fish before returning to their place in the line. Common Terns also moved through the area (in larger numbers) at this time.
After consulting an RSPB (Royal Society for the Protection of Birds) center in the area, I learned that the majority of the Arctic Terns that had bred in the area had done so within the high-security confines of the St. Fergus Gas Works, immediately south of Rattray Head. The gas works colony was apparently a model of stability, with 300-500 pairs breeding in 2006, 450 in 2005, and 445 in 1992. According to the RSPB staff, most of the Arctic Terns from this colony had departed in the first week of August (Aug 3 to Aug 6), but a number of them were apparently still in the area. Closest proximity to the gas works was achieved by a path along the beach and through the dunes to a pond, river and estuary where the river flows into the ocean. 185-200 terns were observed in this location on August 18, with 85-95% of individuals Arctic Terns (confirmed by the RSPB). Based on the data the RSPB had collected within the complex of the gas works itself, most of these Arctic Terns were most likely ones that had bred in the area, with a few that were probably migrants from areas farther to the north. The remaining 5-15% were Common Terns, with a few Sandwich Terns as well. This large group appeared to be resting and preparing to depart, as the majority were sitting on the open ground in close proximity to one another engaging in very little activity other than occasionally picking at Flotsam (seeking insects?).
Ythan Estuary/Sands of Forvie-Black Dog-Saint Cyrus, east-northeast coast Aberdeenshire, Scotland (August 18- August 21)
Continuing south along the coast of Aberdeenshire, I traveled to the River Ythan on the morning of August 19. The estuary of this river is located within a region known as the Sands of Forvie, where a large area of open sandy dunes and beach provides nesting habitat for Little, Common, Arctic, and Sandwich Terns. This area also serves as a crucial refueling site for migratory terns and other birds. Extremely heavy fog for the duration of my visit to the Ythan area reduced visibility to zero meters at times. A total of 8 Arctic, 4 Common, 1 Little, and 15 Sandwich terns were observed. The fog dispelled by the time I reached the Black Dog beaches, another key area for migratory birds, but no terns were present at this site.
Passing through Aberdeen, I arrived at St Cyrus on August 20. Large numbers of Black-legged Kittiwakes and Red-breasted Mergansers were staging in this area, but only a handful of terns were present. Four adult Arctic Terns and two to three juveniles were fishing and perching on nets strung out over the water, and local birdwatchers suggested that I was as suspected approximately 1 week behind the largest wave of migratory Arctic Terns.
Lindisfarne/Holy Island-Farne Isles, Northumberland, England (August 26 - September 1)
Four days spent in Edinburgh prior to my arrival to the northeast corner of England, in part to finalize certain aspects of the project, increased the distance between the Arctic Terns and myself to approximately 1.5 weeks. A boat tour on August 29 to the Farne Isles, the site in conjunction with Coquet Island that holds the most southerly of the large Arctic Tern colonies in Britain, yielded no Arctic Terns. The wardens explained that the majority of the island's breeding terns departed in the first and second week of August (Aug 1-10), and that the largest groups of migratory terns passed through the area in the second and third week of August (Aug 12-20), confirming the 1.5 week distance that I had estimated between the terns and myself. Other areas of the nearby coast such as the beaches of Holy Isle, Bamburgh, and Seahouses also yielded no terns, as expected.
Titchwell-Wells-next-the-Sea-Blakeney (September 1 - September 7)
The Norfolk region, located in southeast England approximately 300 miles from Northumberland, is geographically interesting in that it protrudes farther east into the North Sea than another area on England's eastern coast. This feature of the land is significant for migratory birds, and the north coast of Norfolk provides several key stopover sites for numerous species passing through the area. Because of the physical features, however, of areas north of Norfolk such as the Lincolnshire Coast and Gibraltar Point, migratory birds traveling along the coast appear to be funneled to certain sections of northern Norfolk and not to others (Warden Robert Coleman, pers comm). This patchy distribution of migratory birds makes their passage difficult to assess. On September 3, I observed a small tight group of 12 Sandwich, 3 Common, and 2 Arctic Terns sitting on a sand spit on the Wells beach. Their reluctance to fly at the approach of disturbances such as dogs and people was typical of migratory birds and the fatigue induced from long periods of flight, suggesting that this mixed group of terns was passing through the area. The relative speed of my passage from northeast to southeast England may have shortened the distance between the terns and myself to 1 week, and this small group may have represented the tail end of the large wave of terns that most likely passed through the area.
Eleven miles west of Wells, at the RSPB's Titchwell Nature Reserve, Arctic Terns had only been recorded three times during the summer and fall, 2006: 1 individual on July 11, 2 on August 3, and 3 on August 12. None had been observed in the remaining portion of August or in September. Records from this reserve, however, are slightly biased by the recording method employed. Wardens at this RSPB center do not conduct regular censuses of migratory bird species and numbers as they do at other RSPB sites because of the sheer number of visitors to the reserve (approximately 100,00 per year). Wardens' time is occupied almost entirely with interacting with visitors, and estimates of migratory birds are based on regular reports made by visitors. This source of information, however, is problematic for several reasons: 1, visitors to the reserve often come for the purpose of observing the rare migrants that the area is famous for and may not report the relatively common Arctic Terns that are observed passing on the beach; and 2, distinguishing between Common Terns and Arctic Terns can be difficult for inexperienced observers and may prevent them from reporting any tern sightings in the area. Despite these potentially problematic biases, the records from Titchwell suggest that Arctic Terns do not pass through the area in high numbers. In addition to the low numbers observed in 2006, there were also only 6 records (total of 7 birds) in 2005 and 0 records in 2004. Warden Robert Coleman suggested that the few records at Titchwell may in fact have been a few isolated breeding pairs nesting in the area among the more abundant Common Terns, and that migratory Arctic Terns from farther north either, 1, move along the coast south into an estuary known as The Wash east of Norfolk before flying south overland; or, 2, recognize Blakeney Point (4 miles long, the longest spit on the north norfolk coast, 25-30 miles east of Titchwell) from the Gibraltar Point on the Lincolnshire coast and fly to that point directly rather than over what might appear to be open sea to the Titchwell region.
Following Coleman's suggestions, I made my way to Blakeney Point on September 5 and also examined a book entitled The Birds of Blakeney Point. The book documents the work of multiple researchers and bird watchers and suggested that sightings of Arctic Terns are regular in the autumn as late as October (ie 8 Arctic Terns still present on 16 October 1988). This information seemed to confirm Coleman's theory that migratory terns are funneled farther east than Titchwell to the Blakeny Point region. From the base of the Blakeney Point near the Clay Marshes, I observed Sandwhich and Common Terns, but no Arctic Terns. Ray, a local bird expert and seawatcher leading a bird tour at the Point at the time, claimed that the biggest movement of Arctic Terns to the Point in the autumn had occurred in the last 10 days, with most terns moving east along the shingle beach at the base of the Point north of the Cley Marshes. This observation is in accordance with literature I examined and the theories of Coleman, and confirms my estimate of the separation in time between my passage and that of the terns. James McCallum, another local bird expert, however, reported that Arctic Terns are fairly scarce in the Blakeney area in late August and early September, claiming that these terns generally migrate farther out to sea and are only seen close to the beach during periods of strong onshore winds. His autumn records included 7 Arctic Terns on Aug 2, at least 6 on August 9, 5 on August 12 and 1 on August 14. He also warned, though, that approximately 12 pairs of Arctic Terns had nested on Blakeney Point in 2006, and that there was no way to tell if the migratory terns recorded included members of the small breeding colony in the area. I have contacted several other bird experts in the area, including the reserve manager for the Norfolk Wildlife Trust, who compiles a variety of migratory bird reports, in attempt to clarify the current picture I've developed of the Arctic Tern migration in the Wells-next-the-Sea area.
London
I departed Norfolk on September 7 for London, where I spent several days finalizing logistics for the passage to Africa and completed the examination of Britain's conservation policy's history, issues, etc. The time spent in this city will increase the distance between the terns and myself to approximately 2 weeks, but the relative speed of my imminent journey to Morocco should allow me to realign the timing of my travels with those of the terns.
Conservation Policies and Issues
Canada
Like the UK, Canada has passed a number of bills and acts that have established relatively comprehensive protection for wildlife such as seabirds, and for coastal areas that serve as key bird breeding grounds and migratory stopover sites. Canada is also home to a number of government and non-profit organizations that attempt to implement, monitor, regulate, and enforce the related body of environmental policies. Despite the fairly high level of protection, however, a number of seabirds have been and are in a state of decline. For researchers and conservationists, the situation is understood to be much more complex than requiring no more than the protection currently in place.
In regards to Arctic Terns and seabirds breeding in Canada, the gravest threat is most likely that posed by climate change. In Churchill, it appears that climate shifts have not involved a steady warming trend and related steady decline in bird populations and diversity, as expected, but rather these shifts have been much more dynamic in their nature. Dr. Robert Alison, who has studied the birds and other aspects of the Churchill region for the last 30 years, noted that while warm years appear to be getting warmer (allowing birds to begin breeding earlier), cooler years also appear to be getting cooler. If this trend is confirmed, it means that the oscillations between warm and cool years are getting larger and larger, a trend that can be devastating for breeding birds. While warmer summers may allow birds to begin breeding earlier and provide them with a longer amount of time for raising chicks, an extremely cooler breeding season in the ensuing years could drastically reduce the entire population of birds that had begun to adapt to arriving to the area earlier in the breeding season.
Potentially related to the issue of climate change is the complicated issue of gulls and their relationship to other seabirds. It appears that in both Churchill and Manitoba, and in Musgrave Harbour and Newfoundland, gull populations have potentially grown at the expense of Arctic Terns and other seabirds. Highly advantageous, gulls are quick to adapt to climate shifts that may disturb the food sources of other more specialized seabirds that prey on a limited number of organisms. In addition to prey items that other seabirds hunt (potentially exclusively), gulls also thrive on human refuse, and rapid human growth (often resulting in an increase in the number or size of landfills) in many areas has provided an alternative food source for the gulls. This alternative can lead to large increases in gull populations, which can have a major backlash on other seabirds, as may be occurring in Churchill. Before the large landfill in Churchill closed in 2005, gull populations were increasing over at least a 30 year period (Dr. Robert Alison, pers comm). While other seabirds appeared to undergo population booms and busts in relation to spikes and crashes of specific prey items (ie capelin and other small fish), gulls were able to undergo relatively stable increases, potentially as a result of the availability of readily consumable human refuse. With the closing and burying of the dump in 2005, the now large populations of gulls have apparently had to rely more heavily on the eggs and young of other seabirds. While Arctic Terns aggressively attempt to defend their eggs and young from gulls, these predators appear to be inflicting large losses on terns and other seabirds.
Similarly in Musgrave Harbour, where the human population has been continuously growing, fishermen cite an increase in the number of gulls over the last several decades, and a large dump on the edge of the town may play a role. A number of the gulls nest on offshore islands in direct proximity with the Arctic Terns. Unlike the Churchill region in which space for nesting on the tundra is not a limiting factor, suitable breeding habitat on small islands is extremely limiting. Curtis West, fisherman from Lumsden and local bird expert, described gull increases (with Ring-billed Gulls apparently arriving in just the last 10 years) and a simultaneous decline in tern numbers. If there is a relationship between the two trends, however, it may be more a product of competition over nest space and less the result of predation of gulls on terns.
Another threat to seabirds in Canada is the human harvesting of adults, eggs, and young. While native populations in the Hudson Bay region have traditionally relied more heavily on polar bear, seal, and caribou for sustenance and have not had a large impact on seabirds and Arctic Terns, the people living on the Labrador and Newfoundland coasts (descendants of French, English, and Spanish fishermen from the 15 and 1600s) traditionally harvested large numbers of Arctic Terns (adults, young and eggs) and other seabirds. Regulations imposed within the last half of the century have banned most of such harvesting, but Thick-billed and Common Murres are still hunted off the northern coast of Newfoundland, which didn't become a province of Canada until 1949. Daily bag limits and total annual harvest quotas were established in 1994, but enforcement is difficult and populations are still being reduced beyond sustainable levels.
Beaton Abbott, a retired cod fisherman that I stayed with in Musgrave Harbour on the north Newfoundland coast, offered an interesting perspective on tern harvesting. He explained that when the cod fishery was still booming a half century ago, a large quantity of cod livers were regularly dumped into water around the harbour during the processing of the caught cod. At this time, the Arctic Terns (or stearins, as they are known in Newfoundland) apparently nested in high numbers along the beaches of Musgrave Harbour and took advantage of the byproducts of the cod processing. The children of the fishermen were thus engaged throughout the summer in catching and killing as many birds as possible to supplement the family's meals. Beaton described the pan trap he used to use while his father was at sea and stated that he could catch between 10 and 12 adult terns per day. Another fisherman I met in the area explained that he managed to kill 20 to 30 terns per day with a sling shot. In 1942, there were approximately 700-800 people living in Musgrave Harbour, and young people were most likely able to catch and kill a possible total of 100-200 terns per week for the duration of the breeding season. This human predation most likely impacted both Common and Arctic Terns and it represents a potentially major source of disturbance for the Arctic Terns. As the cod fishery collapsed, the terns apparently shifted from nesting on the beach to nesting farther away on offshore islands, and this shift may have been driven by the levels of human predation on the terns as well as the loss of available cod processing byproducts.
A current threat to seabirds and Arctic Terns comes from the recent developments in the offshore oil industry, particularly in the waters off the north coast of Newfoundland. With the cod moratorium established in 1992 after the crash of the local fishery, the Newfoundland government has been desperate to find another industry capable of filling the massive hole left in the economy by fishery's loss. Funding has been poured into the burgeoning offshore oil industry with apparently substantial initial benefits in terms of increased employment levels and decreases in the emigration of Newfoundland youths. The potential for negative impacts on the coastal environment is high but protective measures have already been established. In May, 2005, a law was passed which banned the dumping of bilge oil from ships, a practice that had resulted in the deaths of approximately 300,000 seabirds per year off the coast of Newfoundland alone.
United Kingdom
An obvious yet important difference between Canada and the United Kingdom in terms of establishment of environmental policy is the issue of land availability. For Arctic Terns in Canada, vast stretches of uninhabited or barely inhabited tundra on the coast of the Hudson Bay and elsewhere provide plenty of suitable breeding habitat, while conversely in the relatively small United Kingdom coastal areas are limited and are in high demand as living space for large populations of birds and humans. It is not surprising that the majority of the Arctic Tern colonies in the United Kingdom are in the far north, on the more isolated and remote Shetland Islands. Nor is it surprising that the organizations which exist in the name of conservation in the UK are highly proactive and aggressive in their management and monitoring of wildlife and protected areas. In addition to well-organized Wildlife Trusts that have been established in most British counties (or shires), there are groups like the Joint National Conservation Committee, Royal Society for the Protection of Birds (RSPB), and the British Trust for Ornithology, which function on a national level. While protection and conservation in some regions may change in the future in conjunction with developments in the offshore oil industry, particularly around the Aberdeenshire coast, and in response to the presence of drifting gill nets, which trap and kill a number of seabirds each year, the system of environmental conservation and protection in the UK is quite advanced. Despite high levels of protection, however, many species of seabirds are declining in the United Kingdom and the situation is typically complex and difficult to assess.
Historically, protection of seabirds in the UK began in the first half of the 20th century. Roy Dennis, professional ornithologist and wildlife consultant, explained to me that a landmark in this history was the RSPB's establishment in the 1930s, which came about partially as a result of pressure from fishermen who relied on seabirds to lead them back to land when conditions at sea became extremely foggy (prior to the development of automatic light houses). At this time, in places like the Shetlands, harvesting of adult seabirds and eggs was common practice, and the fishermen were worried that their lifeline in stormy weather might be eliminated. Following the establishment of the RSPB, people still took eggs and seabirds in more remote areas in the UK through the 1950s, particularly when food was scarce during war time, but this harvest was apparently never on a large enough scale to affect the birds' populations (Roy Dennis, pers comm). In other places such as the Farne Isles, monitoring and protection efforts have been active since at least 1880, and local people in the Northumberland area claim that Saint Cuthbert, a monk who lived on the Farne Isles in the century 600 AD, actively protected eider ducks and other seabirds when he was in residence on the isles almost 1500 years ago.
For Arctic Terns and seabirds in the UK currently, the largest threat is the potential for food shortages, the occurrence of which is most likely related to climate change. While high landings of large predatory fish in the 1960s led to a spike in the abundance of smaller prey fish, and subsequently of seabird populations, those high levels of prey fish have not persisted (Roy Dennis, pers comm). As mentioned already, approximately 500 of the 800 Arctic Tern colonies in the UK are located in the Shetland Islands (Tipling, David, Where to Watch Birds in Britain and Ireland, 2005). Seabirds breeding in this region rely heavily and nearly exclusively on sandeels (a small fish) for prey, and the breeding success of these birds is usually directly linked with the condition of the sandeel populations (Norman Ratcliffe, senior research biologist and seabird specialist, RSPB, pers comm). Sandeel populations crashed and were at extremely low levels from 1985 to 1990, and thus in 1991 sandeel fishing in the Shetlands was banned. Populations of sandeels, however, have suffered since that time despite the protective legislation. Sandeel populations in the years 2001-2005 in the Shetland area and elsewhere showed extremely low levels, and for these 5 consecutive years, Arctic Terns on the Fair Isles, for example, did not fledge a single chick. These drastically low levels of success for Arctic Terns persisted throughout the UK from 2003 to 2004, but from 2004 to 2005, Arctic Tern populations in most parts of Britain conversely showed higher levels of breeding success, with the increases in northeast England the highest since 1986 (JNCC, Seabird Numbers and Breeding Success, 2005 ). On one island in northeast England called Coquet, Arctic Tern sucess from 2004-2005 was in fact the highest since recording began in that area in 1969. The current year, 2006, appears to be one of high success rates as well. In the Shetlands, for example, Arctic Terns and other seabirds fledged a large number of chicks, despite the fact that sandeel levels are still low. Fair Isle Head Warden Deryk Shaw mentioned that one potential response of the seabirds to sandeel shortages is to prey on alternative food sources like pipe fish and lumpsuckers. While pipe fish are abundant in the Shetland Islands, they are not an ideal prey item, as they are less nutritious than sandeels and harder to swallow. In the course of a puffin diet survey, Shaw found 87 uneaten pipe fish in a single burrow that the young had rejected, representing a massive energy expenditure, and loss, for the adults.
Variation in success rates among Arctic Tern colonies in the United Kingdom appears to be related to the potential for drastic differences in the health of local sandeel populations, at times even over very small scales. David Steel, National Trust Head Warden at Inner Farne, noted that sandeels have been abundant in the waters around the Inner Farne and contributed to high seabird success rates in the same year that sandeels have crashed in the region of Coquet Island, located only 18 miles to the south. For researchers like Norman Ratcliffe, the potential for dramatic differences in the success rates of sandeels and seabirds over even very small distances is a confounding factor in determining what appears to be a link in sandeel population status and climate change. According to Ratcliffe, the leading hypothesis is that regime shifts in the North Sea (related to fluctuations in the North Atlantic Oscillation or NAO) led to a change in the timing of phytoplankton blooms. This timing shift subsequently caused a switch in the dominant type of copepod available in the water column. The copepods, which are the major prey of sandeels, and the phytoplankton now apparently bloom in July instead of February, when the sandeels hatch, and thus a mismatch has arisen in predator-prey timing. This mismatch apparently causes the sandeel crashes. While this theory is plausible, Ratcliffe explained that these shifting NAO-based effects should be global and observable on a large scale. Microvariations, however, in sandeel success, abundance, and availability, as have been shown in areas like northeast England, weaken the link between climate change and seabird prey levels, and suggest that other factors might contribute to sandeel (and seabird) population crashes. Ratcliffe cited nutrient run-off from farm land as a potentially major factor contributing to the observed patchiness of success in the UK. Another theory posed by Judy Foster-Smith to explain apparent differences in sandeel availability is that warming in the water column in some regions may force sandeels lower (towards the benthos), suggesting that the problem is not a decrease in the number of sandeels but an alteration of their behavior.
While food availability and sandeel population health are the most serious threats that the well-protected Arctic Terns face, both nest space displacement and predation of chicks by gulls are other issues worth examining. As in Canada, particularly on the north coast of Newfoundland, nest space competition between gulls and Arctic Terns appears to be a much larger problem in the UK than predation of chicks, though such predation does appear to be a problem in some areas. David Steel explained to me that within a gull population, the majority of individuals will not tend to feed on the chicks of other seabirds, but rather that 2 or 3 pairs of the gulls may be specialists that feed almost exclusively on seabird chicks. While predation from fox and mink is a greater threat to seabirds than gull predation, even very small numbers of chick-consuming specialist gulls can apparently have a dramatic effect on a colony of Arctic Terns. Steel noted that in 2001, 246 pairs of Arctic Terns nested on Brownsman Island but fledged only 3 chicks because of heavy predation from specialist gulls in the area. In the following 2 years, wardens shot 7 gulls observed preying on seabird chicks and also set up garden canes in the tern colonies to prevent gulls from alighting on tern nests. The result of these actions, processes that exemplify the relatively aggressive, interactive, and involved style of management adopted by British conservation organizations, was immediately observable. By 2006, 1300 pairs of Arctic Terns persisted on Brownsman and of 120 monitored nests, 108 fledged chicks. Arctic Terns themselves appear to practice some degree of self-management in response to gull predation as well, with colonies on Inner Farne choosing to nest in close proximity to the island's visitor center after 1970 instead of in an area on the open beach where they had nested previously and where gull predation had been much higher.
Conclusion
With strong protection for seabirds and coastal areas in place in Canada and the UK, the next step in terms of maintaining this protection is improving our understanding of other related factors, most notably that of climate change. Norman Ratcliffe is currently preparing a study that will be entitled Regime Shifts of Sandeels and Seabirds in Northern Isles. This study will involve an investigation of the relationship between regime shifts and plankton levels; and an examination of currents and the recruitment of sandeel larvae and juveniles from the Orkneys where they hatch before being transported to places like Fair Isle and the Shetlands. Ratcliffe is also preparing to participate in the International Pole of the Year project, which will involve a collaborative study of Arctic Terns and climate change throughout the Arctic, at sites in and with researchers from Canada, Greenland, UK, and Iceland.
Following my time in the first world breeding grounds of the Arctic Terns, I will proceed to Africa, Antarctica, and South America. In countries like South Africa and Ecuador, where threats to migratory birds like Arctic Terns can undermine the conservation efforts of countries where the birds breed, the approach to protection and policy establishment will most likely bear few similarities to that of countries in North America and Europe. Comparing these diverse areas and the environmental conservation situation unique to each should prove to be highly revealing.
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