• Black-legged Kittiwake Rissa tridactyla adults and chicks share the same diet in the southern Barents Sea 

      Thorvaldsen, Renate; Barrett, Robert T.; Pedersen, Torstein (Journal article; Tidsskriftartikkel; Peer reviewed, 2015)
      The Black-legged Kittiwake Rissa tridactyla population is declining throughout its North Atlantic range. In Norway, the species is classified as Endangered on the Norwegian Red List. Studies of diet are one important requirement for effective management of any species. Because it is easier to sample, chick diet has often been considered a proxy for adult diet in many seabird studies, but the ...
    • Circumpolar dynamics of a marine top-predator track ocean warming rates. 

      Descamps, Sebastian; Anker-Nilssen, Tycho; Barrett, Robert T.; Irons, D.; Merkel, Flemming; Robertson, Gregory J.; Yoccoz, Nigel Gilles; Mallory, Mark L.; Montevecchi, William A.; Boertmann, D.; Artukhin, Yuri; Christensen-Dalsgaard, Signe; Erikstad, Kjell E.; Gilchrist, H. Grant; Labansen, Aili; Lorentsen, Svein Håkon; Mosbech, Anders; Olsen, Bergur; Petersen, Aevar; Rail, Jean-Francois; Renner, Heather M.; Strøm, H.; Systad, Geir Helge; Wilhelm, Sabina I.; Zelenskaya, Larisa (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-04-07)
      Global warming is a nonlinear process, and temperature may increase in a stepwise manner. Periods of abrupt warming can trigger persistent changes in the state of ecosystems, also called regime shifts. The responses of organisms to abrupt warming and associated regime shifts can be unlike responses to periods of slow or moderate change. Understanding of nonlinearity in the biological responses to ...
    • Climate-Driven Ichthyoplankton Drift Model Predicts Growth of Top Predator Young 

      Myksvoll, Mari Skuggedal; Erikstad, Kjell E.; Barrett, Robert T.; Sandvik, Hanno; Vikebø, Frode Bendiksen (Journal article; Tidsskriftartikkel; Peer reviewed, 2013-11-12)
      Climate variability influences seabird population dynamics in several ways including access to prey near colonies during the critical chick-rearing period. This study addresses breeding success in a Barents Sea colony of common guillemots Uria aalge where trophic conditions vary according to changes in the northward transport of warm Atlantic Water. A drift model was used to simulate interannual ...
    • The decline of Norwegian kittiwake populations: modelling the role of ocean warming. 

      Sandvik, Hanno; Reiertsen, Tone K.; Erikstad, Kjell Einar; Anker-Nilssen, Tycho; Barrett, Robert T.; Lorentsen, Svein-Håkon; Systad, Geir Helge; Myksvoll, Mari Skuggedal (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)
      The black-legged kittiwake Rissa tridactyla is a pelagic seabird whose population has recently declined in most parts of the North Atlantic and which is red-listed in most bordering countries. To investigate a possible cause for this decline, we analysed the population dynamics of 5 kittiwake colonies along the Norwegian coast, ranging from 62° to 71° N, over the last 20 to 35 yr. By quantifying the ...
    • The dependence of long-distance migration to North Norway on environmental conditions in the wintering area and en route 

      Barrett, Robert T. (Journal article; Tidsskriftartikkel; Peer reviewed, 2017)
      The onset of bird migration may be under partial endogenous control whereas the timing of movement is flexible with weather and conditions faced by the moving birds being the ultimate cause of variability of arrival dates. This study shows that the early arrival dates of two of three long-distance passerine spring migrants (Willow Warblers Phylloscopus trochilus and Chiffchaffs P. collybita) in North ...
    • Has climate change resulted in a mismatch between the spring arrival of the Common Cuckoo Cuculus canorus and its hosts in North Norway? 

      Barrett, Robert T. (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)
      Analysis of spring arrival dates in North Norway showed advanced arrival of the Common Cuckoo Cuculus canorus but not of four of its most frequently used hosts. No evidence was found of a climate-driven mismatch that might contribute to the decline in the Norwegian Cuckoo population.
    • Later at higher latitudes: large-scale variability in seabird breeding timing and synchronicity 

      Burr, Zofia M.; Varpe, Øystein; Anker-Nilssen, Tycho; Erikstad, Kjell E; Descamps, Sébastien; Barrett, Robert T.; Bech, Claus; Christensen-Dalsgaard, Signe; Lorentsen, Svein-Håkon; Moe, Børge; Reiertsen, Tone Kristin; Strøm, Hallvard (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-05-28)
      In seasonal environments, organisms are expected to optimally schedule reproduction within an annual range of environmental conditions. Latitudinal gradients generate a range of seasonality to which we can expect adaptations to have evolved, and can be used to explore drivers of timing strategies across species’ distribution ranges. This study compares the timing of egg hatching in four seabird ...
    • Levedyktighetsanalyser for norske lomvibestander 

      Erikstad, K.E.; Reiertsen, T.K.; Anker-Nilssen, Tycho; Barrett, Robert T.; Lorentsen, Svein-Håkon; Strøm, H.; Systad, G.H. (Research report; Forskningsrapport, 2007-03)
      Hekkebestandene av lomvi (Uria aalge) langs norskekysten har hatt en sterk nedgang i løpet av de siste 45 årene. Den norske fastlandsbestanden utgjør i dag ikke mer enn ca 15 000 par, mens den til sammenligning ble beregnet til 120-160 000 par i begynnelsen av 1960-årene. Den største bestanden i norske områder finnes i dag på Bjørnøya hvor det hekker ca 100 000 par, men også her er bestanden ...
    • Long-term decline in egg size of Atlantic puffins Fratercula arctica is related to changes in forage fish stocks and climate conditions 

      Barrett, Robert T.; Nilsen, Erlend Birkeland; Anker-Nilssen, Tycho (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)
      Due to major shifts in the marine ecosystem, many seabirds in the NE Atlantic have experienced short- and long-term breeding failures and population changes. One such seabird is the Atlantic puffin Fratercula arctica, the populations of which have declined in Norway at an annual rate of 2% over a ~30 yr period. Parallel to this decline, we found a significant decline in egg volume at 2 widely ...
    • Modelled drift patterns of fish larvae link coastal morphology to seabird colony distribution 

      Sandvik, Hanno; Barrett, Robert T.; Erikstad, Kjell E; Myksvoll, Mari Skuggedal; Vikebø, Frode Bendiksen; Yoccoz, Nigel Gilles; Anker-Nilssen, Tycho; Lorentsen, Svein-Håkon; Reiertsen, Tone; Skardhamar, Jofrid; Skern-Mauritzen, Mette; Systad, Geir Helge (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-05-13)
      Colonial breeding is an evolutionary puzzle, as the benefits of breeding in high densities are still not fully explained. Although the dynamics of existing colonies are increasingly understood, few studies have addressed the initial formation of colonies, and empirical tests are rare. Using a high-resolution larval drift model, we here document that the distribution of seabird colonies along the ...
    • Ocean climate and egg investment in the black-legged kittiwake Rissa tridactyla. 

      Barrett, Robert T.; Erikstad, Kjell E.; Reiertsen, Tone (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-09-14)
      Birds allocate substantial resources to their eggs during the laying period, resources also needed for other concurrent costly processes such as mate acquisition, nest building and site defence. Egg and clutch sizes may thus vary in response to food availability prior to egg laying. We investigated the variation in egg and clutch size of black-legged kittiwakes Rissa tridactyla in a North Norwegian ...
    • On the polar edge: the status of the northern gannet (Morus bassanus) in the Barents Sea in 2015-2016. 

      Barrett, Robert T.; Strøm, H.; Melnikov, Mikhail (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-11-27)
      During its population recovery in the North Atlantic in the early 1900s, the northern gannet (Morus bassanus) established its first colony in Norway at Runde in 1946. Since the 1960s, gannets have established (and later abandoned) several small colonies in the north of the country. These colonies have been regularly monitored, and in 2015–16 ca. 3300 apparently occupied nests (AON) were counted ...
    • Optimal foraging in chick-raising Common Guillemots (Uria aalge) 

      Bugge, Julie; Barrett, Robert T.; Pedersen, Torstein (Journal article; Tidsskriftartikkel; Peer reviewed, 2011)
      The Norwegian population of the Common Guillemot Uria aalge has declined by > 95% since the 1960s, and is classified as critically endangered in the Norwegian Red List. Much of the recent decline has been attributed to reduced food availability, but without extensive documentation of adult diet. Instead, chick diet has been considered a proxy of adult diet during the breeding season in many Norwegian ...
    • Prevailing weather conditions and diet composition affect chick growth and survival in the black-legged kittiwake 

      Christensen-Dalsgaard, Signe; May, Roel F.; Barrett, Robert T.; Langset, Magdalene; Sandercock, Brett K.; Lorentsen, Svein-Håkon (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-10-04)
      To identify priorities for management of seabirds during the breeding season, it is important to understand the ecological mechanisms driving chick growth and survival. In this study, we examined the effects of diet and prevailing weather on the growth and survival of chicks of black-legged kittiwakes Rissa tridactyla over a 10 yr period at Anda, a seabird colony in northern Norway. We show that ...
    • Prey density in non-breeding areas affects adult survival of black-legged kittiwakes Rissa tridactyla 

      Reiertsen, Tone K.; Erikstad, Kjell E.; Anker-Nilssen, Tycho; Barrett, Robert T.; Boulinier, Thierry; Frederiksen, Morten; González-Solís, Jacob; Grémillet, David; Johns, David; Moe, Børge; Ponchon, Aurore; Skern-Mauritzen, Mette; Sandvik, Hanno; Yoccoz, Nigel Gilles (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-08-27)
      In migratory birds, environmental conditions in both breeding and non-breeding areas may affect adult survival rates and hence be significant drivers of demographic processes. In seabirds, poor knowledge of their true distribution outside the breeding season, however, has severely limited such studies. This study explored how annual adult survival rates of black-legged kittiwakes Rissa tridactyla ...
    • Recent decline in body condition of departing Common Guillemots Uria aalge at Hornøya, North Norway 

      Barrett, Robert T. (Journal article; Tidsskriftartikkel; Peer reviewed, 2010)
      Since 1980, there has been large variation and a recent decline in the mass and body condition of Common Guillemot Uria aalge chicks departing from the nest site in NE Norway. This may be related to deterioration in the feeding conditions off the colony and is alarming considering the critically endangered status of the species in Norway. To measure body condition, earlier studies have caught, weighed ...
    • SEAPOP studies in the Barents and Norwegian Seas in 2007 

      Anker-Nilssen, Tycho; Barrett, Robert T.; Bustnes, J.O.; Christensen-Dalsgaard, Signe; Erikstad, K.E.; Fauchald, Per; Lorentsen, Svein-Håkon; Steen, Harald; Strøm, H.; Systad, Geir Helge; Tveraa, Torkild (Research report; Forskningsrapport, 2008-04)
      This is the third annual report of the SEAPOP programme, which was initiated in 2005. In 2007, the work continued at full scale in the Lofoten-Barents Sea area, and similar studies were initiated in the southern part of the Norwegian Sea. The report is divided into three sections. The first is an executive summary, the second presents five selected highlights from the studies in 2007, whereas the ...
    • SEAPOP studies in the Lofoten and Barents Sea area in 2005 

      Anker-Nilssen, Tycho; Barrett, Robert T.; Bustnes, Jan Ove; Erikstad, Kjell E; Fauchald, Per; Lorentsen, Svein Håkon; Steen, Harald; Strøm, Hallvard; Systad, Geir Helge Rødli; Tveraa, Torkild (Research report; Forskningsrapport, 2006)
      This is the first annual report from SEAPOP, a long-term seabird programme aiming to provide and maintain base-line knowledge needed for an improved management of marine areas. For several reasons, the activities in the initial year were restricted to the Lofoten and Barents Sea area, but the programme is designed for implementation on the full national scale within a few years. The report ...
    • SEAPOP studies in the Lofoten and Barents Sea area in 2006 

      Anker-Nilssen, Tycho; Barrett, Robert T.; Bustnes, Jan Ove; Erikstad, Kjell Einar; Fauchald, Per; Lorentsen, Svein-Håkon; Steen, Harald; Strøm, Hallvard; Systad, Geir Helge; Tveraa, T (Research report; Forskningsrapport, 2007-04)
      This is the second annual report of the SEAPOP programme, which was initiated in 2005. In 2006, the programme was extended to the near full scale in the Lofoten-Barents Sea area, but it is aimed for implementation at the national level within few years. The report is divided into three sections. The first is an executive summary, the second presents five selected highlights from the studies in ...
    • SEAPOP. Et nasjonalt sjøfuglprogram for styrket beslutningsstøtte i marine områder 

      Anker-Nilssen, Tycho; Bustnes, J.O.; Erikstad, K.E.; Lorentsen, Svein-Håkon; Tveraa, T.; Strøm, H.; Barrett, Robert T. (Research report; Forskningsrapport, 2005-01)
      SEAPOP (Seabird population management and petroleum operations) er et nasjonalt, kunnskapsoppbyggende program om sjøfugl tilrettelagt for å gi styrket beslutningsstøtte for marine områder. Konseptet ble først utviklet for oljeindustrien i et samarbeid mellom Norsk institutt for naturforskning (NINA) og Den norske stats oljeselskap as (Statoil), men er senere videreutviklet i samarbeid med Norsk ...