Using multiple abundance estimators to infer population trends in Atlantic Puffins

2002 ◽  
Vol 80 (6) ◽  
pp. 1014-1021 ◽  
Author(s):  
Anna M Calvert ◽  
Gregory J Robertson
Keyword(s):  
Breeding Season ◽  
Total Population ◽  
Age Distribution ◽  
Breeding Population ◽  
Population Trends ◽  
High Fecundity ◽  
Closed Population ◽  
Fratercula Arctica ◽  
Abundance Estimates ◽  
Stable Age Distribution

We used five techniques to estimate the number of Atlantic Puffins (Fratercula arctica) using a study plot on Gull Island, Newfoundland, during the 2000 breeding season. Grubbing of burrows yielded an estimate of a breeding population of 522 (95% CI: 364–668) Atlantic Puffins on this plot. Attendance counts of birds standing on the plot consistently underestimated the breeding population. A closed-population estimator with sighting heterogeneity estimated that of the 535 Atlantic Puffins banded since 1997, 370 (336–404) used the plot in 2000. Using 370 birds as the marked population, a corrected Lincoln–Petersen index estimated a total population of 1712 (1233–2191) based on captured birds. Based on resights of birds, ratios of banded birds to total attendance estimated 2927 (2608–3335), and the Bowden estimator gave 3502 (3054–3950) Atlantic puffins. We projected an age-based matrix using literature values, and extracted the proportions of nonbreeding birds and young birds expected at a stable age distribution and compared the proportions with observed values. Based on the large number of nonbreeders suggested by the abundance estimates, we suspect that this population (i) is stable or increasing, (ii) includes breeding-age Atlantic Puffins that do not breed, and (iii) has been enjoying high fecundity in recent years.

scholarly journals Predictions of FluSurge 2.0 methodology on hospital utilization during the Covid-19 outbreaks in several countries

2021 ◽  
Vol 13 ◽  
pp. 184797902110205
Author(s):  
Francisco Reyes-Santias ◽  
Isabel Barrachina-Martinez ◽  
David Vivas-Consuelo
Keyword(s):  
Total Population ◽  
Age Distribution ◽  
Scenario Planning ◽  
Hospital Utilization ◽  
Hospital Treatment ◽  
Health Security ◽  
Support Resources ◽  
Hospital Beds ◽  
The Usa ◽  
America South

Application of the Flusurge 2.0 methodology to predict the needs of conventional hospital treatment, intensive care, and respiratory support resources as a consequence of coronavirus disease (COVID-19) in several countries. Different countries of the following continents have been selected: Europe, Asia, Africa, North America, South America, and Oceania. Variables: Total population and age distribution; Number of COVID19 infections; Number of deaths from COVID19; Number of non-ICU hospital beds; Number of ICU beds; Number of ventilators. Method: The proposed possible scenario planning is based on the application of FluSurge 2.0 Software, developed by The Johns Hopkins Center for Health Security (CHS/CDC). Saturation of conventional hospitalization is expected in India, Uganda, Nepal, and Haiti; there is a forecast of saturation for ICU beds in all sample countries except Turkey. Ventilator saturation is expected in all countries of the sample except Argentina, Austria, Brazil, France, United Kingdom, Japan, South Korea, Norway, Poland, Turkey and the USA. The model shows, for a percentage greater than 50% of the countries, difficulties related to the saturation of their ICU units, and the use of ventilators.

scholarly journals Breeding of the common kingfisher Alcedo atthis at the Boracka River

2016 ◽  
pp. 105-112 ◽  
Author(s):  
Ivana Novcic
Keyword(s):  
Breeding Season ◽  
Riparian Vegetation ◽  
Breeding Population ◽  
Stream Habitat ◽  
Breeding Density ◽  
The Common

The breeding population of the common kingfisher Alcedo atthis was studied in the Boracka River area in 2006 and 2007. A high breeding density was docu?mented in 2007 with five breeding pairs recorded along the 1.4 km section of a stream habitat. All of the studied nests were placed in vertical banks without excessive riparian vegetation, while the distance between adjacent nests ranged 120-430 m. The same nest holes were used in both years, although birds excavated a couple of new ones in 2007. One pair bred in two consecutive years; the same pair had two breeding attempts in 2007, while three breeding attempts were recorded for one male. Birds used the same holes for subsequent clutches or excavated new nests. Also, one nest was used by different pairs in the same breeding season. In the study period 21 individuals were banded - none of the juvenile in?dividuals was recaptured, suggesting that the fledglings dispersed shortly after they had left their nests. Also, none of the breeding individuals was recaptured at the river outside the breeding season.

scholarly journals STUDI LALAT PENGOROK DAUN LIRIOMYZA SPP. PADA PERTANAMAN BAWANG DAUN, DAN PARASITOID OPIUS CHROMATOMYIAE BELOKOBYLSKIJ & WHARTON (HYMENOPTERA: BRACONIDAE)

2009 ◽  
Vol 9 (1) ◽  
pp. 22-31
Author(s):  
Rusli Rustam ◽  
Aunu Rauf ◽  
Nina Maryana ◽  
Pudjianto Pudjianto ◽  
Dadang Dadang
Keyword(s):  
Age Distribution ◽  
Host Density ◽  
Field Studies ◽  
Reproductive Value ◽  
Laboratory Studies ◽  
Demographic Parameter ◽  
Liriomyza Huidobrensis ◽  
Stable Age Distribution ◽  
Net Reproduction ◽  
Density Results

Studies on Leafminer Liriomyza spp. in Green Onion Fields, and Parasitoid Opius chromatomyiae Belokobylskij & Wharton (Hymenoptera: Braconidae).  Field studies were conducted to determine population abundance of leafminers and their parasitoids in green onion fields in Puncak, West Java. In addition to that, laboratory studies were carried out to determine demographic parameter of Opius chromatomyiae as well as response of parasitoid to increasing host density. Results revealed that green onions were infested by two species of leafminers, Liriomyza huidobrensis and Liriomyza chinensis.  Leafminer flies emerged from Erwor leaves (54.5) were significantly higher than those of RP leaves (18.65) (P = 0.0005). However, number of  leafminer flies caught on sticky traps was not statistically different (P = 0.297).  Two species of parasitoid, Hemiptarsenus varicornis and O. chromatomyiae, were associated with leafminers in green onion fields. Higher number of parasitoids emerged from Erwor leaves (13.68) as compared to RP (6.90) (P =0.0007 ). However, level of parasitization were 24.36% on Erwor and 28.45% on RP, and was not significantly different (P = 0.387). Laboratory studies indicated that net reproduction (Ro) of O. chromatomyiae was 28.55, generation time (T) 15.96 days, intrinsic growth rate 0.21, and total of reproductive value 223.64.  The stable age distribution of parasitoid were 37.93% eggs, 24.92% larvae, 20.36% pupae and 16.78% adults.  The parasitoid showed functional response type II to increasing host density, with a = 0.08 and Th = 2.58.

scholarly journals Long-term population trends of the Red-legged CormorantPhalacrocorax gaimardion the Argentine coast

2014 ◽  
Vol 25 (2) ◽  
pp. 234-241 ◽  
Author(s):  
ANA MILLONES ◽  
PATRICIA GANDINI ◽  
ESTEBAN FRERE
Keyword(s):  
Population Change ◽  
Breeding Population ◽  
Temporal Variations ◽  
Population Trends ◽  
World Population ◽  
Ocean Productivity ◽  
Marine Primary Productivity ◽  
Long Term Trend ◽  
Positive Effect

SummaryThe world population of Red-legged CormorantPhalacrocorax gaimardiis reasonably small and has showed rapid declines. In Argentina, this species breeds in 13 localities and is considered as ‘Endangered’ by the national government. In this study, we provide information about population trends of the Red-legged Cormorant on the Argentine coast, between 1990 and 2009. We also discuss whether these trends could be related to sea surface temperature and marine primary productivity, both of which are considered oceanographic factors that can affect breeding seabirds. The long-term trend in the breeding population showed a slight decrease of 1.2% per year. Seven colonies showed an average population change < 1. Periods of stability and increase were identified over the study period, but they were insufficient to compensate for the decreases. The largest colony of Red-legged Cormorants (La Mina, with more than 55% of the entire breeding population) seems to determine the overall population trend. We did not find a direct relationship between the overall number of Red-legged Cormorants and the two oceanographic factors analysed. However, our analysis detected a positive effect of ocean productivity close to the coast on the largest colony at the beginning of the breeding season, suggesting that coastal ocean productivity could be an important factor affecting temporal variations in the Argentinian population.

Diet and breeding of the rufous spiny bandicoot Echymipera rufescens australis, Iron Range, Cape York Peninsula

2007 ◽  
Vol 29 (2) ◽  
pp. 169 ◽  
Author(s):  
D.I. Shevill ◽  
C.N. Johnson
Keyword(s):  
Breeding Season ◽  
Litter Size ◽  
Reproductive Rate ◽  
High Fecundity ◽  
Iron Range ◽  
Seed Disperser ◽  
Faecal Analysis ◽  
Live Trapping ◽  
Cape York ◽  
Trapping Grid

A population of the rufous spiny bandicoot Echymipera rufescens australis was studied for 14 months by live-trapping, and diets were determined by faecal analysis. The population had a high density (approximately 48 individuals on a trapping grid of 2.25 ha). A wide variety of foods were eaten, but fruits and seeds contributed the largest proportion of material to faeces, followed by invertebrates, fungi and dicot plants. Echymipera rufescens may potentially be a significant seed disperser for some plants, such as Pandanus zea. There was a short breeding season, with births occurring between December and March. Females produced one or two litters per year. Mean litter size was just under three, and litter size increased with the mother?s mass. Females produced a mean of 4.9 young per year. We conclude that although E. rufescens is a ?typical? bandicoot in that it is omnivorous and has high fecundity, it is more frugivorous and has a somewhat lower reproductive rate than other Australian bandicoots.

Catastrophic ongoing decline in Cambodia’s Bengal Florican Houbaropsis bengalensis population

2019 ◽  
Vol 30 (2) ◽  
pp. 308-322 ◽  
Author(s):  
SIMON P. MAHOOD ◽  
CHAMNAN HONG ◽  
SON VIRAK ◽  
PHEARUN SUM ◽  
STEPHEN T. GARNETT
Keyword(s):  
Sex Ratio ◽  
East Asia ◽  
Breeding Season ◽  
Total Population ◽  
East Asian ◽  
South East Asia ◽  
Conservation Area ◽  
Conservation Programme ◽  
Tonle Sap ◽  
Rate Of Decline

SummaryIn 2013 a prediction was made that the South-East Asian subspecies of Bengal Florican Houbaropsis bengalensis blandini would be extinct within 10 years. In 2018 we conducted a survey in the Tonle Sap floodplain, Cambodia, of the last population of Bengal Florican in South-East Asia. We found that the rate of decline in displaying males was 55% over five years, a decline comparable to that recorded between 2005–2007 and 2012. The estimated number of displaying males in 2018 was 104 (95% CI: 89–117), down from 216 (156–275) in 2012. We also conducted surveys by flushing birds in the non-breeding season, which indicated that the sex ratio of males to females is 3:1. We therefore estimate that the total population of adult Bengal Floricans in Cambodia in 2018 was 138 (119–156), making H. b. blandini the most threatened bustard taxon. The number of sites that support displaying male Bengal Floricans was reduced from 10 to four between 2012 and 2018. Between 2012 and 2018 we monitored numbers of displaying males in most years at the sites that support 80% of the total population. The only site where numbers of birds are stable is Stoung-Chikraeng Bengal Florican Conservation Area, where there were 44 (25–63) displaying males in 2018. This is the only site that has an ongoing NGO-government conservation programme. Our data indicate that Bengal Floricans are lost from sites when the area of grassland falls below 25 km2. We found evidence that displaying male Bengal Floricans abandon display territories when grassland is lost, this also creates hope that they may disperse and could colonise newly created habitat. All remaining sites that support Bengal Floricans in Cambodia are imperilled and we outline what must be done to reduce the possibility that H. b. blandini will be extinct by 2023.

Interactive Behaviour of Puffins (Fratercula Arctica L.) and Skuas (Stercorari Us Parasiticus L.)

Behaviour ◽  
1971 ◽  
Vol 40 (3-4) ◽  
pp. 263-281 ◽  
Author(s):  
P.R. Grant
Keyword(s):  
Breeding Season ◽  
Selective Advantage ◽  
Breeding Birds ◽  
The Other ◽  
Breeding Colony ◽  
Fratercula Arctica ◽  
Food Fish ◽  
Interactive Behaviour ◽  
The Way

AbstractPuffins fly to their burrows with food (fish) in their beaks for the single chick they raise. Skuas chase puffins and induce them to drop their food. If the skuas do not catch the falling food before it reaches the ground gulls drive the skuas away from the food and secure it for themselves. These interactions were studied quantitatively for two weeks at a breeding colony of puffins at Vik on the mainland of Iceland. The only conspicuous response of the puffins to the skuas was one of avoidance at the end of the breeding season when the frequency of arrival of breeding puffins at the colony was low; the puffins turned around in flight and flew back towards the sea. Some of the characteristics of chases which ended with food being released by the puffins were identified. Chases involving more than one skua tended to be more successful (i.e. food released) than those with one skua. Chases of puffins away from the colony were more successful than those towards the colony. Chases of incoming puffins were more successful when initiated far from the colony than when initiated close to it. Low flying puffins appeared to be chased preferentially. From these observations some idea can be gained of the way in which selection acts upon the puffins and skuas. For the skua there appear to be optimal positions from which to start chasing a food-carrying puffin, and selection acts against those skuas which choose incorrect positions and gain no reward after expending much energy in a chase. For the puffin there is a selective advantage when returning to the colony with food for the chick in flocking with non-breeding birds without food. This stratagem maximizes the difficulties of the skua detecting a food-carrying puffin early enough to start a chase with a chance of success. Late breeding by the puffin is selected against because, when the other parents have left the colony, it is comparatively easy for a skua to identify and successfully attack a food-carrying puffin. The difficulties of avoiding a chase by a skua under these conditions are reduced if the puffin delays its final flight to the colony until the skuas are either absent or 'out of position'. Selection acts against those puffins which do not take this avoiding action.

scholarly journals Novel methods reveal shifts in migration phenology of barn swallows in South Africa

2011 ◽  
Vol 279 (1733) ◽  
pp. 1485-1490 ◽  
Author(s):  
Res Altwegg ◽  
Kristin Broms ◽  
Birgit Erni ◽  
Phoebe Barnard ◽  
Guy F. Midgley ◽  
...  
Keyword(s):  
South Africa ◽  
Breeding Season ◽  
Environmental Variability ◽  
Southern Oscillation ◽  
Bird Species ◽  
Breeding Population ◽  
Migratory Bird ◽  
Recent Climate ◽  
Breeding Grounds ◽  
Barn Swallows

Many migratory bird species, including the barn swallow ( Hirundo rustica ), have advanced their arrival date at Northern Hemisphere breeding grounds, showing a clear biotic response to recent climate change. Earlier arrival helps maintain their synchrony with earlier springs, but little is known about the associated changes in phenology at their non-breeding grounds. Here, we examine the phenology of barn swallows in South Africa, where a large proportion of the northern European breeding population spends its non-breeding season. Using novel analytical methods based on bird atlas data, we show that swallows first arrive in the northern parts of the country and gradually appear further south. On their north-bound journey, they leave South Africa rapidly, resulting in mean stopover durations of 140 days in the south and 180 days in the north. We found that swallows are now leaving northern parts of South Africa 8 days earlier than they did 20 years ago, and so shortened their stay in areas where they previously stayed the longest. By contrast, they did not shorten their stopover in other parts of South Africa, leading to a more synchronized departure across the country. Departure was related to environmental variability, measured through the Southern Oscillation Index. Our results suggest that these birds gain their extended breeding season in Europe partly by leaving South Africa earlier, and thus add to scarce evidence for phenology shifts in the Southern Hemisphere.

scholarly journals Census of the Southern Giant Petrel population of the Falkland Islands 2004/2005

2008 ◽  
Vol 18 (2) ◽  
pp. 118-128 ◽  
Author(s):  
Tim A. Reid ◽  
Nic Huin
Keyword(s):  
Total Population ◽  
Current Knowledge ◽  
Conservation Status ◽  
Breeding Population ◽  
Knowledge Development ◽  
Falkland Islands ◽  
Giant Petrel ◽  
Strong Indication ◽  
Southern Giant Petrel ◽  
Near Threatened

AbstractA complete census was taken of all colonies of Southern Giant Petrels Macronectes giganteus within the Falkland Islands in 2004/05. The breeding population of the islands was estimated to be approximately 19,529 pairs (range 18,420–20,377). Southern Giant Petrels were found to breed in 38 locations around the islands, with colony size varying from one to 10,936. The majority of colonies were concentrated around the south of Falkland Sound, and to the west of West Falkland. Whilst there has been no previous census of the total population of the islands, there is a strong indication that the population has increased since the 1950s. The reasons for such an increase in population remain unclear in light of current knowledge. Development of our understanding of the breeding biology and demography of this species in the Falkland Islands is necessary, as is the need to conduct such a census every five years, with a few key colonies to be monitored every season. From the results obtained here, the conservation status of the Southern Giant Petrel, currently listed as ‘Vulnerable’, could be downgraded to ‘Near Threatened’.

scholarly journals Foraging ecology and choice of feeding habitat in the New Zealand Fairy Tern Sternula nereis davisae

2013 ◽  
Vol 24 (1) ◽  
pp. 72-87 ◽  
Author(s):  
STEFANIE M. H. ISMAR ◽  
TOM TRNSKI ◽  
TONY BEAUCHAMP ◽  
SARAH J. BURY ◽  
DAVID WILSON ◽  
...  
Keyword(s):  
New Zealand ◽  
Stable Isotope ◽  
Breeding Season ◽  
Foraging Ecology ◽  
Avicennia Marina ◽  
Breeding Population ◽  
Breeding Bird ◽  
Breeding Sites ◽  
Sand Spit ◽  
Feeding Habitat

SummaryNo published information is available on the foraging ecology and choice of feeding habitat of New Zealand’s rarest breeding bird: the New Zealand Fairy Tern (NZFT) Sternula nereis davisae. To address this gap, we conducted an assessment of the largest remaining breeding population at Mangawhai Harbour, Northland, New Zealand, during the chick-rearing period of the 2010/2011 breeding season. We combined visual tracking of birds with prey surveys and stable isotope analyses, and we present the first quantitative assessment of NZFT foraging. We recorded 405 foraging dives that show NZFT foraging habitat includes the water edges, shallow channels, and pools on the tidal flats of mangrove-lined (Avicennia marina var. resinifera) parts of the estuary; tidal pools on mud- and sandflats in the mid-estuary and lower harbour; the shallow margins of the dredged main channel in the lower harbour; the oxbow lagoons on the sand spit; and coastal shallows. Our study identifies the mangrove-lined highly tidal and shallow mid-estuary and the lagoon on the sand spit as foraging hotspots for the Mangawhai breeding population of the NZFT. The prey survey employed a seine-net sampling method at identified NZFT foraging sites and yielded 4,367 prey-sized fish of 11 species, two of which had not previously been reported in Mangawhai Harbour, as well as numerous shrimps. The most abundant fish were gobies of the genus Favonigobius. Our stable isotope results highlight gobies as the most important prey for NZFT chick rearing, also indicating that flounder Rhombosolea sp. contribute to NZFT diet. We raise the possibility that shrimps may also constitute a substantial diet component for NZFT, potentially providing up to 21% of diet mass for adult birds. While our results provide a first basis to understanding the feeding ecology of NZFT during their breeding season in order to facilitate conservation planning, further research is required to address inter-annual variation and to identify key foraging grounds for this Critically Endangered bird at other breeding sites.

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