Number Of Breeding Pairs Research Articles

Cumulative Effect of Trophic and Weather–Climatic Factors on the Population Dynamics of the Vole-Eating Birds of Prey in Their Breeding Habitats

In the period 2001–2016, the authors studied the combined effect of trophic and weather–climatic factors on the population dynamics of three vole-eating bird of prey species on the study area in northern Moscow region, Crane Homland Reserve (56.7573° N, 37.792° E). The numbers of breeding pairs of the Common kestrels (Falco tinnunculus), Long-eared owls (Asio otus) and Short-eared owls (A. flammeus), as well as abudance of small mammals, were counted in the spring and summer months every year. Different indicators characterizing the weather–climatic conditions in the study area over the period of existence of the nesting groups of bird species were calculated based on the data of the nearest meteorological station. The simulation results showed that the numbers of the Long-eared owls depended significantly only on the trophic factor (β = 0.77 ± 0.1). The numbers of breeding pairs of the Short-eared owls and the Common kestrels depended significantly on both factors. The influence of the trophic factor on the change in the numbers of predators was the higher for the Short-eared owl (β ± SE = 1.64 ± 0.16) and the less for the Common kestrel (β = 0.38 ± 0.12). For the Common kestrel, the impact of climatic and weather factors (β = 0.41 ± 0.09) on its numbers slightly exceeded that of the trophic factor. For Short-eared owl, the effect of the climatic factor (β = 0.36 ± 0.09) was 4.5 times less than that of the trophic factor. A combination of temperature and humidity in the spring period can significantly influence the amplitude and frequency of fluctuations in the numbers of the three species of birds of prey under consideration.

Delayed predator-prey collapses: the case of black-legged kittiwakes and Iberian sardines

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 631:201-207 (2019) - DOI: https://doi.org/10.3354/meps13164 Delayed predator-prey collapses: the case of black-legged kittiwakes and Iberian sardines A. Martínez-Abraín1,*, P. Santidrián Tomillo2, J. Mouriño3, S. Tenan4, D. Oro5,6 1Universidade da Coruña, Facultad de Ciencias, Evolutionary Biology Group, Campus da Zapateira s/n, 15071 A Coruña, Spain 2The Leatherback Trust, Goldring-Gund Marine Biology Station, Playa Grande, Costa Rica 3Arcea, Xestión de Recursos Naturais S.L., Velázquez Moreno 9, oficina 305, 36201 Vigo, Spain 4MUSE - Museo delle Scienze, Sezione di Zoologia dei Vertebrati, Corso del Lavoro e della Scienza, 3, 38122 Trento, Italy 5Instituto Mediterráneo de Estudios Avanzados IMEDEA (CSIC-UIB), Miquel Marquès 21, 07190 Esporles, Spain 6Centre d’Estudis Avançats de Blanes CEAB (CSIC), Acces Cala Sant Francesc 14, 17300 Blanes, Spain *Corresponding author: a.abrain@udc.es ABSTRACT: We analysed the long-term (1975-2017) population response of a colony of a marine top predator, the black-legged kittiwake Rissa tridactyla, to the population dynamics of sardine Sardina pilchardus, its main local prey. The study site (Sisargas Islands, Spain) is located at the southernmost edge of the geographical distribution of the predator. Kittiwake counts of breeding pairs started with the discovery of the colony (1975), likely close to the actual year of first colonization. Sardine landings by age class (1978-2016) were taken from the International Council for the Exploration of the Sea (ICES) database. Sequential t-test analysis revealed that a regime shift of the oldest sardine age class (age 6+) took place in 1991 and that kittiwakes experienced a regime shift in the number of breeding pairs in 1993, 2 yr after the prey shift. Multiple autocorrelation functions for the detrended time series of sardines and kittiwakes indicated an autocorrelation with a time lag of 2 yr. Despite much reduced fishing effort, sardine densities have not recovered since the collapse, likely due to changes in large-scale atmospheric circulation in the Northern Hemisphere in the late 1990s. Kittiwakes at Sisargas have not recovered demographically, remaining nearly extinct during the last ca. 20 yr. Although we lack detailed demographic data for the studied kittiwake population, we suggest that massive breeding failure and subsequent dispersal to higher-quality patches might explain the rapid non-linear collapse in breeding population density. We discuss some behavioural social responses that may have occurred during and after the collapse to explain the dynamics of the study colony. KEY WORDS: Population crash · Black-legged kittiwakes · Time delay · Non-linearities · Predator-prey dynamics · Food availability · Iberian sardine · Fisheries collapse Full text in pdf format Supplementary material PreviousNextCite this article as: Martínez-Abraín A, Santidrián Tomillo P, Mouriño J, Tenan S, Oro D (2019) Delayed predator-prey collapses: the case of black-legged kittiwakes and Iberian sardines. Mar Ecol Prog Ser 631:201-207. https://doi.org/10.3354/meps13164 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 631. Online publication date: November 21, 2019 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2019 Inter-Research.

First data on breeding success of Croatian inland colonies of Common TernSterna hirundo

AbstractIn 2018 and 2019, the breeding success of two Common Tern colonies on artificial lakes near the River Sava in Zagreb, Croatia, was studied. The colonies were visited weekly from May to July and we collected data on phenology, number of breeding pairs, clutch size as well as egg and chick survival. We also conducted a comparison between early and late breeders. Hatching and fledging success was within previously observed ranges, apart from a low hatching success on Siromaja in 2019. The smaller colony on Siromaja had a higher productivity in both years than the colony on Rakitje, although in 2018 an avian pox virus killed much of the late chicks on Rakitje. Early breeders seem to have had higher hatching success and average clutch size. Furthermore, a greater proportion of them managed to hatch all their eggs compared to late breeders, but the differences were not statistically significant. Our study provided baseline data for future monitoring of phenology and breeding success with regard to the management of breeding colonies.

37 years of Common Tern Sterna hirundo breeding at Sečovlje Salina

Abstract Years ago, the Common Tern Sterna hirundo was known to nest in Slovenia along larger watercourses. Today it only breeds locally in artificially built nesting areas. On the seashore, its nesting was confirmed for the first time in 1983, when 9 pairs bred in the Sečovlje Saltpans. In the same year, we started mapping the breeders in the Sečovlje Saltpans, which has continued till this very day. Since 2010, we have been systematically collecting data on the number of fledged birds. In 1991, the number of breeding pairs increased, which coincides with the increase in other parts of the Mediterranean. Since 1991, the size of the breeding population has been quite stable, ranging from 30 to 70 pairs. The Common Tern’s breeding success in the Sečovlje Saltpans is poor, mainly due to precipitation (40% of all unsuccessful nests) and predation (35%). Long, dry periods without rainfall have a positive effect on the hatching and fledging success. Appropriate water management, artificial islands and access to nesting sites control can prevent the disturbance caused by visitors and, in part, predators such as foxes and martens. At the Sečovlje Saltpans, the Common Tern’s survival depends entirely on the active management. The expected climate change, with increasing sea level rise and consequently more frequent flooding of low-lying areas, further aggravates its existence and survival in the Sečovlje Saltpans.

The decline and rise of the Kransberg Cape Vulture colony over 35 years has implications for composite population indices and survey frequency

Long‐term monitoring is key for detecting population declines. Composite indices allow researchers to combine trends from disparate monitoring programmes into a single estimate of population change. Inferences from composite indices, however, are limited to the time periods and areas studied. We show that the number of breeding pairs in a colony of Cape Vultures Gyps coprotheres in South Africa declined between the years 1983 and 2003 but increased in both the number of breeding pairs and fledglings per pair from 2004 to 2017. We performed a retrospective power analysis determining the minimum annual frequency with which the colony could have been monitored without sacrificing inference into population trends. This power analysis revealed the post‐2003 population increase would not have been apparent if we skipped more than 2 years between surveys. We incorporated our estimates into a previously published composite index for Cape Vultures that considered only data collected pre‐2000 and demonstrate that the inference is unchanged if the trend from the decline period or the entire study is incorporated, yet if only the trend during the period of population increase is used, there is no longer a statistically significant decline across the species’ range. Our results demonstrate the utility of long‐term monitoring because if our study had concluded before 2003, there would be little evidence of the current population increase at Kransberg.

Sea buckthorn berries Hippophae rhamnoides L. predict size and composition of a great tit population Parus major L

In seasonal environments variation in food abundance in the non‐breeding season is thought to affect songbird population dynamics. In a unique tit‐sea buckthorn berry system we can estimate the berry abundance and both the tit consumption and population dynamics. Six hundred nest boxes were available to great and blue tits Cyanistes caeruleus for breeding in spring and roosting in winter. We followed the dynamics including the recapture histories of individually marked great tits from 2008 to 2014. In each year we estimated 1) the winter sea buckthorn berry availability, 2) an index of berry consumption in December based on the colour of the faeces of roosting birds, 3) the number of breeding great and blue tits, 4) both recapture probability and the return rate of the great tits and 5) immigration rates. December berry abundance positively predicted the number of breeding pairs of both species in the subsequent season and great tit return rates in the second half of the winter. There was support for a sex specific berry effect on the adult return rate in the great tit: female return rate was associated less strongly to berry abundance than male return rate. This skewed the sex ratio of the local breeders in the following breeding season. Intriguingly, annual berry consumption in December was not related to berry abundance, and individuals consuming more berries tended to have slightly lower return rates. Reproductive rate was not related to berry abundance. There was hardly support for a relation between immigration rates of first year breeders and berry abundance. Taken together these results imply that berry stock not only affected population size but also the population composition through sex specific exchange with the surroundings. Since population density covaried with berry abundance, density dependent effects provide an alternative explanation for the patterns observed.

Change in nest site and population size of great cormorants (Phalacrocorax carbo) in relation to different Ardeidae species in inland breeding sites in Korea

We investigated the changes in the population size and inter-specific space usage for breeding in mixed breeding sites of the great cormorant (Phalacrocorax carbo), grey heron (Ardea cinerea), great egret (Ardea alba modesta) and intermediate egret (Egretta intermedia) in Gammul-myeon, Goesan-gun, Chungcheongbuk-do, South Korea, in 2016–2017. These species bred in two adjacent habitats (site A and site B). The number of breeding pairs of all species and the size of the breeding area at site B increased in 2017. In 2017, great cormorants at site B occupied the breeding sites previously occupied by the other species in 2016, while the grey heron and great egret occupied the sites around the great cormorant breeding site. The heights of nest trees and nests of great cormorant and grey heron did not differ temporally, but these heights in site B were significantly higher than those in site A for great cormorants. For great egrets, these greatly decreased in site B in 2017. Thus, the great cormorant either moved to favourable nest sites for breeding success or selected nest sites used by the herons in the previous year. Further studies of these two possibilities are necessary.

The Northern Bald Ibis Geronticus eremita in Morocco since 1900: Analysis of ecological requirements

SummaryThe Northern Bald Ibis (NBI) Geronticus eremita, is an ‘Endangered’ bird species of which only very few wild breeding colonies have survived along the Atlantic coast of south-west Morocco. This paper analyses ecological conditions of the 72 breeding sites of the NBI that have been known since 1900 in Morocco. Characterisation of breeding sites is based on physical criteria (elevation above sea level, geomorphology, mean annual precipitation and types of landscape) as well as land use, vegetation cover, infrastructure and types of settlement within three perimeters (0–1 km, > 1–5 km and > 5–10(20) km) using Google Earth satellite images. Statistical analyses of the number of breeding pairs, fledglings and rainfall during different quarters of the year from 1994 to 2016 in the two remaining breeding sites in Souss-Massa National Park and Tamri showed expected patterns as well as unexpected differences between the two localities. Based on our findings and indications in the literature, we suggest general and specific recommendations for potential future translocation projects of the NBI. Based on the analysis of the 28 breeding colonies existing after 1977, two elements emerge as the most important prerequisites: a low level of disturbances at the breeding sites and adequate feeding areas at a reasonable distance of 5–15 km.

Pigeon and Poultry Breeders, Friends or Enemies of the Northern Goshawk Accipiter gentilis? A Long-Term Study of a Population in Central Poland.

Simple SummaryThe population of goshawks crashed in the middle of the 20th century due to persecution, forest management practices, and the usage of toxic pesticides (DDT) in agriculture. Now, it has rebuilt, yet the population trend is not equal across countries. Here, we focused on a goshawk population in central Poland for which monitoring started in the 1980s (high densities were recorded at that time of 16.3 pairs/100 km2) to see how changing environmental factors influenced the current population trend. In the field and forest mosaic, these birds build their nests in small forest complexes, but important prey tend to be caught near farmsteads. This has previously resulted in the persecution of the birds by farmers. Anthropogenic food (poultry and domestic pigeons) played a key role in their population density. Consequently, when the anthropogenic food base was limited (due to changes in the Polish farmland), population abundance dropped by half. As supplementary prey (including small-game and most corvid species) were not abundant, goshawks could not replace their staple food of anthropogenic origin. This demonstrates the complex way in which socioeconomic changes in agriculture can influence a raptor population: both positively (fewer cases of persecution are being recorded now) and negatively (small-scale breeding of pigeons and poultry became unimportant and unprofitable, and small game abundance decreased due to changes in farming practices and farmland structure). In this study, we focused on a goshawk population in central Poland (study area 105 km2, forests 24 km2, seven small forest complexes) which was monitored long-term (with high densities recorded in the 1980s of 16.3 pairs/100 km2 despite persecution by farmers) to analyse how environmental factors (prey availability and changes in the forest structure) influenced population abundance, breeding parameters, and diet composition. The study was undertaken from 2011–2018, and the results were compared with published data from two previous study periods (1982–1992 and 2001–2003). The number of breeding pairs dropped from 17.1 to 8.0; the breeding success was around 75% in all study periods. The selection of nesting trees followed the changes in stand species and age structure. More nesting attempts per one nest were recorded in the current time period (1.7 vs. 1.1), which probably reflected lower anthropopressure (i.e., no cases of persecution were recorded in this study). Diet composition seemed to follow changes in the prey availability: The share of domestic pigeons and poultry (the main prey in the 1980s) as well as small game dropped, while the share of Eurasian jay and wood pigeon increased. Our studies suggested that anthropogenic food (poultry and domestic pigeons) played a key role for the goshawk population in the transformed habitats of the field and forest mosaic.

Population status of the endemic royal penguin (Eudyptes schlegeli) at Macquarie Island

Penguins globally are of conservation concern due to rapid decreases in many populations. Royal penguins (Eudyptes schlegeli) are endemic to Macquarie Island and its offshore islands and the current population status of this species is unknown. Here, we present a contemporary population estimate, undertaken in 2016 using precise global position system technology. Between August and December 2016, all royal penguin colonies were visited and the number of breeding pairs estimated by mapping the perimeters of colonies and applying a nest density estimate. The royal penguin population was estimated at 750,037 breeding pairs (range 669,538–830,154 pairs). The estimate is slightly lower than a previous estimate in 1984, but given the refined methods it was not possible to establish a significant difference or that a decrease in the population has not occurred. Future censuses utilising a consistent methodology are required to more accurately determine the current population trend. Establishing the current status of the royal penguin population will help assess the species vulnerability to several threats that are impacting similar species in the sub-Antarctic region, and inform conservation planning and management.

Determinants of the little auk (Alle alle) breeding colony location and size in W and NW coast of Spitsbergen.

Many seabirds breed in large aggregations, making it difficult to estimate their population size and habitat preferences. This knowledge is particularly important considering their function in food webs and ecosystem services. In this study, we investigated the factors affecting distribution and abundance of the little auk Alle alle, a seabird considered a keystone species of the Arctic ecosystem. We performed the study on the W and the NW coast of Spitsbergen. Using Generalized Additive Models (GAMs) and Conditional Inference Tree (CIT) we examined factors related to presence/absence and size (estimated number of breeding pairs) of the little auk colonies. We also tested the nesting preferences for geographical features such as aspect, slope angle, altitude, solar radiation, rock type, and distance to foraging grounds. Our findings indicate that the occurrence of little auk breeding colonies is non-random and highly attributed to environmental factors. The probability of colony occurrence was significantly associated with altitude (negative relationship; preference to sites situated lower), solar radiation (positive relationship; the higher radiation, the more likely colony occurrence) and slope (positive relationship; the steeper a slope, the more likely colony occurrence), whilst aspect appeared non-significant (though the probability of colony occurrence peaked at southern slopes). Colony size was significantly associated with rock type (larger colonies in amphibolite and quartzite). The distance to foraging grounds did not appear to affect the probability of colony occurrence and size, implying that birds may choose optimal breeding sites at the cost of longer foraging flights. We estimated the Spitsbergen little auk breeding population at 728 529 (5–95% CI: 479 312–986 352). Spitsbergen comprises ca 1.9% (95% CI: 1.2%–2.7%) of the world breeding population and represents the third most important breeding area for the species, following the W and the E coast of Greenland.

Indirect Influence of African Swine Fever Outbreak on the Raven (Corvus corax) Population.

Simple SummaryThe persecution of ravens ceased in the middle of the 20th century, and consequently their abundance started to rise in most European countries. Ravens are food opportunists that can eat plants, prey on animals, and feed on garbage dumps. However, carrion plays a crucial role in their diet. In Central Poland, the carrion of farm animals (disposed of illegally) was thought to be the main food source for ravens. This changed radically in February 2014, after the first case of African swine fever (ASF) in Poland, and the introduction of strict procedures for the utilization of pig and wild boar carcasses to stop the spread of the virus. This decrease in carrion availability influenced the raven population; ravens changed their diet, i.e., instead of feeding on the carrion of pigs (previously their main dietary component), they ate (among others) the carrion of domestic dogs and cats, and also preyed on small vertebrates. Consequently, the number of breeding raven pairs decreased, and birds produced fewer fledglings. This research showed how certain human activities influence wildlife. The illegal disposal of dead animals, motivated by the desire to save money, resulted in abundant food sources for ravens and an increase in population size.Carrion plays a crucial role in the raven’s diet. In the past, domestic pig carrion was widely available in Poland. This changed with an African swine fever (ASF) outbreak and the introduction of strict procedures aimed at stopping the virus from spreading. We compared data from Central Poland (field and forest mosaic, study area of 105 km2) for two periods, i.e., before (2011–2014) and after the ASF outbreak (2015–2018). In breeding seasons, nests of ravens were found, juveniles were counted, and the time when juveniles left their nests was recorded. Diet composition data were based on pellet analysis and direct observations of feeding birds. The number of breeding pairs dropped from 12.3 to 7.5 in the second period. Breeding parameters were similar. However, birds in the second period had fewer fledglings per successful pair. Domestic pig carrion was found to be an important food item, and with its limited supply, ravens changed their diet, i.e., they fed on the carrion of dogs and cats or preyed on small vertebrates more often. Overall, our study points to a crucial role of the availability of the carrion of big farm animals (i.e., domestic pig) in maintaining the high density of breeding raven populations.

PASSER HISPANIOLENSIS IS A NEW NESTING SPECIES ON NORTH-WESTERN COAST OF THE CRIMEAN PENINSULA

Aim. The aim of the research is to study the potential nesting sites of the Spanish sparrow (Passer hispaniolensis) on the northwest coast of Crimea. Methods. Material was compiled during 2016-2018. The generally accepted methods of road and foot route census study were applied. Nesting stations were explored: nests of storks, birds of prey and corvids, forest belts and reed beds. Results. On the basis of research, the presence of Passer hispaniolensis in the north-western Crimea, in particular, within the borders of the Lebyazhy Islands («Swan Islands») specially protected natural area, has been established. It is revealed that for nesting, this species of sparrow prefers the areas close to fields and is not often found in human settlements. During the nesting period, an increase in the number from 15 to 45 pairs was noted. The greatest number of breeding pairs of spanish sparrow is found in the nests of the white stork. Late arriving birds form colonies on trees in close proximity to stork nests. Conclusion. Nesting of Passer hispaniolensis is most likely due to changes in the hydrological regime and land use structure, since rice crop rotation (until 2014) has been replaced by other grain crops (barley, wheat) and tilled crops (sunflower, maize). Thus, at present, the breeding ornithofauna of the protected area is represented by 92 species of birds.

Rapid decline in the number of breeding pairs of Tachypleus tridentatus and the degradation of sandbanks for spawning due to cumulative bay mouth modifications at Tsuyazaki Cove, Fukuoka, Japan

Rapid decline in the number of breeding pairs of <i>Tachypleus tridentatus</i> and the degradation of sandbanks for spawning due to cumulative bay mouth modifications at Tsuyazaki Cove, Fukuoka, Japan

Effects of forest management practices in clearings on breeding performance of the Red-backed Shrike (Lanius collurio)

The structure and quality of breeding habitats play an essential role for breeding success of individuals and thus, the viability of populations. Knowledge on habitat requirements can guide management practises to ensure optimal conditions for breeding. In this study, we investigate the effect of different habitat features and forest management strategies on the breeding performance of Red-backed Shrikes (Lanius collurio) breeding in Gribskov forest, Denmark. We found that the availability of available perches for hunting is the main predictor having a positive effect on number of breeding pairs and fledglings. It was also positively associated with the number of years that the clearing has been occupied by breeding pairs. Furthermore, clearings with grazing animals contained breeding pairs for more years than clearings without grazing, suggesting improved foraging conditions in clearings with low vegetation. Our results provide direct applications for forestry management for improving the conservation status of this species.

Breeding population of Black Stork, Ciconia nigra, in Italy between 1994 and 2016

The Black Stork Ciconia nigra, following an expansion on European scale, started breeding in Italy in 1994 with one pair in the Piedmont Region and one in the Calabria Region. Since then, the breeding pairs established in Italy have progressively increased up to 18 in 2016, and they are currently in Piedmont, Lazio, Campania, Molise, Apulia, Basilicata and Calabria. However, the number of breeding pairs could be higher than 20, as indicated by records and observations of adults and juveniles, during the breeding period in potentially suitable nesting areas. Despite the low population density in Italy, the trend in the breeding population in Northwest and in Southern Central regions seems to show a slight and high increase respectively. Productivity, breeding success and fledging rate have been considered and analysed. A difference between the two macro areas has been found in the choice of nesting sites, which is on trees for Northwest couples, and cliffs for Southern Central couples. It is necessary to further explore the reason why the small Northwest population does not show any increase and range expansion compared to the Southern Central one.

Satellite factors influencing the impact of recreational activities on wildlife

Satellite factors influencing the impact of recreational activities on wildlife

Nest sites as a key resource for population persistence: A case study modelling nest occupancy under forestry practices.

Natural nest sites are important breeding resource in terms of population dynamics, especially in forest systems where nest trees limit populations or timber harvesting destroys nests. Nest structures usually have a long life and can be reused by breeding pairs across multiple breeding seasons, so studying their dynamics is of relevance for biodiversity conservation. In this study, we develop a dynamic model to evaluate nest site availability and its influence on the breeding settlement of a forest raptor community composed of booted eagle (Hieraaetus pennatus), common buzzard (Buteo buteo) and northern goshawk (Accipiter gentilis) in a Mediterranean forest ecosystem in southeast Spain. This model approach is also applied to analyse the influence of forestry practices on the dynamics of occupied nests for a simulated period (2010–2050). The simulated scenarios include unmanaged forest and timber harvesting practices of clearcuttings every ten years considering two factors: the age class of trees for clearcutting (40, 50, 60 and 70 years old) and the type of forest management (with or without nest protection). Our simulated results show that the number of breeding pairs is constant during the period without timber harvest, whereas breeding pairs gradually decrease in the scenario of clearcutting trees aged from 70 to 50-years without nest protection, and populations become extinct with the clearcutting of 40-year old trees. Considering the practice of clearcutting and nest protection, nest occupancy can reach the maximum number of occupied nests for the scenarios of cutting 70 and 60-year old trees, and maintain populations without extinction for the scenarios of cutting 40-year old trees. We conclude that nest sites (whether occupied or not) are key resources for increasing the occupancy of the forest raptor community and that nest protection measures buffer the effects of clearcuttings, thus preventing population extinction.

A long-term study of gentoo penguin (Pygoscelis papua) population trends at a major Antarctic tourist site, Goudier Island, Port Lockroy

Gentoo penguins Pygoscelis papua breed at a number of sites at the West Antarctic Peninsula, including Goudier Island, Port Lockroy—the longest studied location for tourist-penguin interactions in the Antarctic. These penguins annually encounter some of the highest numbers of tourists in the whole of Antarctica. Using yearly count data from all ten colonies on Goudier Island, we report changes in long-term population size and breeding success over a 21 year period (1996/1997 to 2016/2017), documenting inter-annual variability in numbers of breeding pairs and chicks fledged (productivity). We found a 24.5% (1.4% per annum) decrease in breeding pairs; similar declines were evident in breeding pairs at six colonies visited by tourists as well as at four unvisited colonies. Breeding success also declined, with chick numbers declining in visited (53.7%, 3.8% per annum) and unvisited colonies (59.8%, 4.6% per annum). While gentoo penguin numbers are increasing regionally, we reveal a recent decline in the Goudier Island population occurring simultaneous with increases in tourist numbers from 262 in 1996/1997 to 19,688 in 2016/2017. Analyses suggest a complex situation with different possible drivers of change. There was a significant negative effect of increasing air temperature and shifts in sea ice variables on breeding pairs. However, similar statistical support showed a significant link existed between year and visitors, with higher numbers of visitors negatively affecting penguin numbers. Based on our results we recommend increased precaution in management at Goudier Island, and initiation of similar studies at other frequently visited penguin sites in Antarctica.

Distribution and Abundance of Breeding Striated Caracaras in the Falkland Islands (Malvinas)

We conducted surveys of breeding pairs of the endemic and globally “Near Threatened” Striated Caracara (Phalcoboenus australis) on 79 outer islands in the Falklands archipelago (Islas Malvinas) during the austral-summer breeding seasons of 2013–2014 and 2014–2015. A total of 354 breeding pairs (defined as pairs with evidence of egg-laying), or an archipelago-wide adult breeding population of at least 0.05 birds/km2 was recorded. An additional 477 probable breeding pairs also were found. The distribution of breeding pairs remains similar to that found during surveys in the 1990s and 2000s. Grand Jason, Steeple Jason, New Island, Beauchene Island, and Bird Island, the five islands with the highest numbers of breeding pairs, accounted for half of the total breeding population. “Vegetationally pristine” islands with dense areas of tussac grass (Poa flabellata) and high densities of small burrowing seabirds—namely Bird Island, Saddle Island, and Beauchene Island—supported the highest densities of breeding pairs. Eighty percent of all pairs occurred on National Nature Reserves or on privately owned nature sanctuaries. Our surveys suggest that sustained protection of key breeding sites is critical for the long-term conservation of this species. We recommend that populations of Striated Caracaras at Tierra del Fuego also be surveyed and that the global population status of the species be reassessed.