Lake Bant tern colony

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The Lake Bant tern colony is a breeding colony of common terns (Sterna hirundo) at Lake Bant (Banter See in German) in the port city of Wilhelmshaven, north-western Germany. It is the subject of a long-term research project carried out by the Institute of Avian Research (Heligoland Bird Observatory).

Bird colony large congregation of birds at a particular location

A bird colony is a large congregation of individuals of one or more species of bird that nest or roost in proximity at a particular location. Many kinds of birds are known to congregate in groups of varying size; a congregation of nesting birds is called a breeding colony. Colonial nesting birds include seabirds such as auks and albatrosses; wetland species such as herons; and a few passerines such as weaverbirds, certain blackbirds, and some swallows. A group of birds congregating for rest is called a communal roost. Evidence of colonial nesting has been found in non-neornithine birds (Enantiornithes), in sediments from the Late Cretaceous (Maastrichtian) of Romania.

Common tern Migratory seabird in the family Laridae with circumpolar distribution

The common tern is a seabird in the family Laridae. This bird has a circumpolar distribution, its four subspecies breeding in temperate and subarctic regions of Europe, Asia and North America. It is strongly migratory, wintering in coastal tropical and subtropical regions. Breeding adults have light grey upperparts, white to very light grey underparts, a black cap, orange-red legs, and a narrow pointed bill. Depending on the subspecies, the bill may be mostly red with a black tip or all black. There are a number of similar species, including the partly sympatric Arctic tern, which can be separated on plumage details, leg and bill colour, or vocalisations.

Lake Bant Lake in Wilhelmshaven, Germany

Lake Bant, or Banter See in German, is an artificial lake in the North Sea port city of Wilhelmshaven in north-west Germany. It is about 2.6 km long and 0.5 km wide. It was originally part of the harbour complex created by enclosing part of Jade Bight bordering the city’s waterfront for military and industrial use. It used to contain naval facilities, including a submarine base. Now separated from the port, it is used mainly for recreation and research. It is surrounded by parkland, recreational facilities, up-market housing, research institutes and company offices.

Contents

Common tern colony at Banter See in Wilhelmshaven, Germany Flussseeschwalbenkolonie Banter See.jpg
Common tern colony at Banter See in Wilhelmshaven, Germany
Aerial view of colony site 2012-05-28 Fotoflug Cuxhaven Wilhelmshaven DSCF9472.jpg
Aerial view of colony site

Location

The colony breeds on six concrete islands, which were originally used as a loading dock for the now abandoned U-boat harbour at Banter See. The site is protected as a natural monument of the city. [1] The colony was attracted to the site in 1984 using taped lures, after their previous breeding site had been destroyed.

U-boat German submarine of the First or Second World War

U-boat is an anglicised version of the German word U-Boot[ˈuːboːt](listen), a shortening of Unterseeboot, literally "underseaboat." While the German term refers to any submarine, the English one refers specifically to military submarines operated by Germany, particularly in the First and Second World Wars. Although at times they were efficient fleet weapons against enemy naval warships, they were most effectively used in an economic warfare role and enforcing a naval blockade against enemy shipping. The primary targets of the U-boat campaigns in both wars were the merchant convoys bringing supplies from Canada and other parts of the British Empire, and from the United States to the United Kingdom and to the Soviet Union and the Allied territories in the Mediterranean. German submarines also destroyed Brazilian merchant ships during World War II, causing Brazil to declare war on the Axis powers in 1944.

Natural monument natural or natural/cultural feature of outstanding or unique value

A natural monument is a natural or natural/cultural feature of outstanding or unique value because of its inherent rarity, representative of aesthetic qualities or cultural significance.

Marked common terns sitting on a box equipped with antenna and scales. Common Terns on box with antenna and scale.JPG
Marked common terns sitting on a box equipped with antenna and scales.

Colony development

From an initial 90 breeding pairs the colony grew rapidly to a maximum of 530 pairs in 2005. Following several years of low breeding success, lower juvenile survival and delayed first breeding attempts, the colony was reduced to 430 pairs in 2011. [2] This was most likely due to lack of food; breeding success is highly variable, dependent on food availability in the Wadden Sea. Banter See terns feed mostly on juvenile herring, sprat and smelt. [3] The predation rate is low, since the islands are protected from terrestrial predators, but in some years there have been high losses caused by owls.

Wadden Sea An intertidal zone in the southeastern part of the North Sea (Netherlands, Germany and Denmark)

The Wadden Sea is an intertidal zone in the southeastern part of the North Sea. It lies between the coast of northwestern continental Europe and the range of low-lying Frisian Islands, forming a shallow body of water with tidal flats and wetlands. It has a high biological diversity and is an important area for both breeding and migrating birds. In 2009, the Dutch and German parts of the Wadden Sea were inscribed on UNESCO's World Heritage List and the Danish part was added in June 2014.

Herring forage fish, mostly belonging to the family Clupeidae

Herring are forage fish, mostly belonging to the family Clupeidae.

Sprat

Sprat is the common name applied to a group of forage fish belonging to the genus Sprattus in the family Clupeidae. The term also is applied to a number of other small sprat-like forage fish. Like most forage fishes, sprats are highly active, small, oily fish. They travel in large schools with other fish and swim continuously throughout the day.

Bug being released from dummy egg after sucking blood from breeding bird. Bug in dummy-egg.tif
Bug being released from dummy egg after sucking blood from breeding bird.

Methods

Since 1980 all chicks have been ringed and breeding success estimated. Since 1992, all fledglings (more than 5000 so far) also get a passive transponder inserted, identifying them individually. [4] [5] An automatic antenna recording system identifies individual terns when they return to the breeding site each season, without birds having to be trapped. Antennas are distributed in prominent places around the colonies and also placed around nests to identify breeding partners. Scales are also distributed around the colony, to record individual weights throughout the season. This system collects data on arrival dates, body weights, breeding partners and breeding success of hundreds of individuals each breeding season with minimal disturbance. These life histories provide important information on the population ecology of long-lived birds.

Bird ringing attachment of tag to a wild bird to enable individual identification

Bird ringing or bird banding is the attachment of a small, individually numbered metal or plastic tag to the leg or wing of a wild bird to enable individual identification. This helps in keeping track of the movements of the bird and its life history. It is common to take measurements and examine conditions of feather molt, subcutaneous fat, age indications and sex during capture for ringing. The subsequent recapture or recovery of the bird can provide information on migration, longevity, mortality, population, territoriality, feeding behavior, and other aspects that are studied by ornithologists. Other methods of marking birds may also be used to allow for field based identification that does not require capture.

Transponder device that emits an identifying signal in response to a received signal

In telecommunication, a transponder is a device that, upon receiving a signal, emits a different signal in response. The term is a portmanteau for transmitter-responder. It is variously abbreviated as XPDR, XPNDR, TPDR or TP.

Life history theory is an analytical framework designed to study the diversity of life history strategies used by different organisms throughout the world, as well as the causes and results of the variation in their life cycles. It is a theory of biological evolution that seeks to explain aspects of organisms' anatomy and behavior by reference to the way that their life histories—including their reproductive development and behaviors, life span and post-reproductive behavior—have been shaped by natural selection. A life history strategy is the "age- and stage-specific patterns" and timing of events that make up an organism's life, such as birth, weaning, maturation, death, etc. These events, notably juvenile development, age of sexual maturity, first reproduction, number of offspring and level of parental investment, senescence and death, depend on the physical and ecological environment of the organism.

Terns tend to improve with age. Older birds arrive at the breeding site earlier and lay their eggs earlier than their younger counterparts. [6] [7] They increase their breeding success with age and experience, until around the age of 15, when senescence seems to set in. [8] Despite senescence, birds that reach very old age have the highest life-time reproductive success.

Senescence gradual deterioration of function characteristic of most complex lifeforms

Senescence or biologicalaging is the gradual deterioration of functional characteristics. The word senescence can refer either to cellular senescence or to senescence of the whole organism. Organismal senescence involves an increase in death rates and/or a decrease in fecundity with increasing age, at least in the later part of an organism's life cycle.

Physiological analyses of hormones and other blood parameters, as well as genetic analyses are also performed at this colony. Blood samples of breeding birds are taken without trapping, as this reduces stress, which could change blood parameters, for example by increasing stress hormones. This is done using Mexican triatomine blood-sucking bugs ( Dipetalogaster maxima ), that are placed hungry into a hollowed-out dummy egg, which is placed into the nest of the brooding bird. The bug is able to suck blood through small holes in the wall of the dummy egg. The blood is subsequently extracted from the bug and analysed. [9] [10]

Triatominae subfamily of insects

The members of the Triatominae, a subfamily of the Reduviidae, are also known as conenose bugs, kissing bugs, assassin bugs, or vampire bugs. Other local names for them used in the Latin Americas include barbeiros, vinchucas, pitos, chipos and chinches. Most of the 130 or more species of this subfamily feed on vertebrate blood; a very few species feed on other invertebrates. They are mainly found and widespread in the Americas, with a few species present in Asia, Africa, and Australia. These bugs usually share shelter with nesting vertebrates, from which they suck blood. In areas where Chagas disease occurs, all triatomine species are potential vectors of the Chagas disease parasite Trypanosoma cruzi, but only those species that are well adapted to living with humans are considered important vectors. Proteins released from their bites have been known to induce anaphylaxis in sensitive and sensitized individuals.

Related Research Articles

Seabird Birds that have adapted to life within the marine environment

Seabirds are birds that are adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations. The first seabirds evolved in the Cretaceous period, and modern seabird families emerged in the Paleogene.

Tern family of seabirds

Terns are seabirds in the family Laridae that have a worldwide distribution and are normally found near the sea, rivers, or wetlands. Terns are treated as a subgroup of the family Laridae which includes gulls and skimmers and consist of eleven genera. They are slender, lightly built birds with long, forked tails, narrow wings, long bills, and relatively short legs. Most species are pale grey above and white below, with a contrasting black cap to the head, but the marsh terns, the Inca tern, and some noddies have dark plumage for at least part of the year. The sexes are identical in appearance, but young birds are readily distinguishable from adults. Terns have a non-breeding plumage, which usually involves a white forehead and much-reduced black cap.

Arctic tern A bird in the family Laridae with a circumpolar breeding distribution covering the Arctic and sub-Arctic regions of Europe, Asia, and North America

The Arctic tern is a tern in the family Laridae. This bird has a circumpolar breeding distribution covering the Arctic and sub-Arctic regions of Europe, Asia, and North America. The species is strongly migratory, seeing two summers each year as it migrates along a convoluted route from its northern breeding grounds to the Antarctic coast for the southern summer and back again about six months later. Recent studies have shown average annual roundtrip lengths of about 70,900 km (44,100 mi) for birds nesting in Iceland and Greenland and about 90,000 km (56,000 mi) for birds nesting in the Netherlands. These are by far the longest migrations known in the animal kingdom. The Arctic tern flies as well as glides through the air. It nests once every one to three years ; once it has finished nesting it takes to the sky for another long southern migration.

Roseate tern A bird in the family Laridae

The roseate tern is a tern in the family Laridae. The genus name Sterna is derived from Old English "stearn", "tern", and the specific dougallii refers to Scottish physician and collector Dr Peter McDougall (1777–1814). "Roseate" refers to the bird's pink breast in breeding plumage.

Whiskered tern species of bird

The whiskered tern is a tern in the family Laridae. The genus name is from Ancient Greek khelidonios, "swallow-like", from khelidon, "swallow". The specific hybridus is Latin for hybrid; Pallas thought it might be a hybrid of white-winged black tern and common tern, writing "Sterna fissipes [Chlidonias leucopterus] et Hirundine [Sterna hirundo] natam”.

Royal tern species of bird

The royal tern is a tern in the family Laridae. The genus name is from Ancient Greek Thalasseus, "fisherman", from thalassa, "sea". The specific maximus is Latin for '"greatest".

Forsters tern species of bird

The Forster's tern is a tern in the family Laridae. The genus name Sterna is derived from Old English "stearn", "tern", and forsteri commemorates the naturalist Johann Reinhold Forster.

Greater crested tern Seabird in the family Laridae

The greater crested tern, also called crested tern or swift tern, is a tern in the family Laridae that nests in dense colonies on coastlines and islands in the tropical and subtropical Old World. Its five subspecies breed in the area from South Africa around the Indian Ocean to the central Pacific and Australia, all populations dispersing widely from the breeding range after nesting. This large tern is closely related to the royal and lesser crested terns, but can be distinguished by its size and bill colour.

Ythan Estuary

The Ythan Estuary is the tidal component of the Ythan River, emptying into the North Sea 19 kilometres (12 mi) north of Aberdeen, Scotland. The estuary’s tidal action extends a 7 kilometres (4.3 mi) inland and has characteristic widths of between 250 metres (820 ft) and 780 metres (2,560 ft). Besides the tidal channel there are interfaces to the upland dunes including mudflats, sand beaches and shingle flats. Reaches of salt marsh occur, but they are primarily near the Waterside Bridge and the mouth of the Tarty Burn, a small tributary river. Based upon the habitat of the moorland bordering the east of the Ythan River near the mouth, this estuary is the most significant coastal moorland in the northern United Kingdom.

Bant is town in Flevoland, the Netherlands.

Kerguelen tern species of bird

The Kerguelen tern is a tern of the southern hemisphere.

Fauna of the Cocos (Keeling) Islands

The terrestrial fauna of the Cocos (Keeling) Islands is unsurprisingly depauperate, because of the small land area of the islands, their lack of diverse habitats, and their isolation from large land-masses. However, the fauna dependent on marine resources is much richer.

South American tern species of bird

The South American tern is a species of tern found in coastal regions of southern South America, including the Falkland Islands, ranging north to Peru and Brazil. It is generally the most common tern in its range. The smaller, highly migratory common tern closely resembles it. The specific epithet refers to the "swallow-like" forked tail feathering.

Norderoog German halligen island

Norderoog is one of the ten German halligen islands of the North Frisian Islands in the Wadden Sea, which is part of the North Sea off the coast of Germany. A part of Hooge municipality, the island belongs to the Nordfriesland district.

Minsener Oog island

Minsener Oog, also Minser Oog or Minsener Oldeoog, is an uninhabited East Frisian island that belongs to the parish of Wangerooge in the north German district of Friesland in the state of Lower Saxony. It has been artificially enlarged through the construction of groynes.

Seabird breeding behavior

The term seabird is used for many families of birds in several orders that spend the majority of their lives at sea. Seabirds make up some, if not all, of the families in the following orders: Procellariiformes, Sphenisciformes, Pelecaniformes, and Charadriiformes. Many seabirds remain at sea for several consecutive years at a time, without ever seeing land. Breeding is the central purpose for seabirds to visit land. The breeding period is usually extremely protracted in many seabirds and may last over a year in some of the larger albatrosses; this is in stark contrast with passerine birds. Seabirds nest in single or mixed-species colonies of varying densities, mainly on offshore islands devoid of terrestrial predators. However, seabirds exhibit many unusual breeding behaviors during all stages of the reproductive cycle that are not extensively reported outside of the primary scientific literature.

References

  1. ↑ Becker, P. H. 1996. Flussseeschwalben (Sterna hirundo) in Wilhelmshaven. Oldenburger Jahrbuch 96. Isensee Verlag, Oldenburg
  2. ↑ Szostek, K. L., and P. H. Becker. 2012. Terns in trouble: demographic consequences of low breeding success and recruitment on a common tern population in the German Wadden Sea. Journal of Ornithology 153:313-326
  3. ↑ Dänhardt, A., and P. Becker. 2011. Herring and Sprat Abundance Indices Predict Chick Growth and Reproductive Performance of Common Terns Breeding in the Wadden Sea. Ecosystems 14:791-803.
  4. ↑ Becker, P. H., and H. Wendeln. 1997. A New Application for Transponders in Population Ecology of the Common Tern. The Condor 99:534-538.
  5. ↑ Becker, P. H., T. H. G. Ezard, J.-D. Ludwigs, H. Sauer-Gürth, and M. Wink. 2008. Population sex ratio shift from fledging to recruitment: consequences for demography in a philopatric seabird. Oikos 117:60-68
  6. ↑ Ezard, T. H. G., P. H. Becker, and T. Coulson. 2007. Correlations between age, phenotype, and individual contribution to population growth in common terns. Ecology 88:2496-2504.
  7. ↑ Becker, P. H., T. Dittmann, J.-D. Ludwigs, B. Limmer, S. C. Ludwig, C. Bauch, A. Braasch, and H. Wendeln. 2008. Timing of initial arrival at the breeding site predicts age at first reproduction in a long-lived migratory bird. PNAS 105:12349-12352.
  8. ↑ Rebke, M., T. Coulson, P. H. Becker, and J. W. Vaupel. 2010. Reproductive improvement and senescence in a long-lived bird. PNAS:1-6
  9. ↑ Bauch, C., S. Kreutzer, and P. Becker. 2010. Breeding experience affects condition: blood metabolite levels over the course of incubation in a seabird. Journal of Comparative Physiology B 180:835-845.
  10. ↑ Riechert, J., O. Chastel, and P. H. Becker. 2012. Why do experienced birds reproduce better? Possible endocrine mechanisms in a long-lived seabird, the common tern. General and Comparative Endocrinology 178:391-399.

Coordinates: 53°30′40″N8°06′19″E / 53.5110°N 8.1052°E / 53.5110; 8.1052

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