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.

Grey petrel population on Campbell Island 14 years after rodent eradication

2016 ◽  
Vol 29 (3) ◽  
pp. 209-216 ◽  
Author(s):  
Graham C. Parker ◽  
Kalinka Rexer-Huber ◽  
David Thompson
Keyword(s):  
New Zealand ◽  
Breeding Population ◽  
Population Estimate ◽  
Population Estimates ◽  
Commercial Fisheries ◽  
Breeding Sites ◽  
Incidental Capture ◽  
Rodent Eradication ◽  
Campbell Island ◽  
Future Population

AbstractPopulations of grey petrels have declined globally due to both incidental capture in commercial fisheries and predation by introduced mammals at breeding sites. In the New Zealand region, grey petrels only breed on Campbell and Antipodes islands. Rats were successfully eradicated from Campbell Island in 2001. We assessed the spatial extent and conducted the first quantitative population estimate of the grey petrel population on Campbell Island and surrounding islets. There was an estimated c. 96 pairs (95% CI: 83, 109) of breeding grey petrels from the four colonies. Since work was conducted during the middle of the chick-rearing stage, this is an underestimate of the breeding population. The Campbell Island grey petrel breeding population remains small. Our study provides a baseline for future population estimates of grey petrels on Campbell Island.

Manage one beach or two? Movements and space-use of the threatened hooded plover (Thinornis rubricollis) in south-eastern Australia

2009 ◽  
Vol 36 (4) ◽  
pp. 289 ◽  
Author(s):  
Michael A. Weston ◽  
Glenn C. Ehmke ◽  
Grainne S. Maguire
Keyword(s):  
Breeding Season ◽  
Space Use ◽  
Breeding Population ◽  
Breeding Period ◽  
Research Attention ◽  
Breeding Sites ◽  
Kernel Analysis ◽  
Eastern Australia ◽  
Southern Central ◽  
Breeding Seasons

An understanding of space use and dispersal of a wildlife species is essential for effective management. We examined the movements of a beach-dwelling, threatened population of hooded plover (Thinornis rubricollis) in southern central Victoria, Australia, by analysing sightings of colour-banded birds (4897 sightings; 194 birds tracked for up to 9 years). Most movements were relatively short (5050 ± 305 m), with 61.4% <1 km and 95.3% <20 km; they lacked directional or sexual bias. The extent of coastline used by individual birds was 47.8 ± 58.0 km. Regional differences in average distances moved by adults were apparent. For adults, movement rates (mean distance per day) were higher during the non-breeding season than during the breeding season. Non-breeding adults generally remained close to their partners (non-breeding, 456.3 ± 163.9 m; breeding, 148.2 ± 45.3 m). Largest flock sizes were recorded during the non-breeding period, and flocking was not uniformly distributed along the coast but appeared to be concentrated in particular locations. The frequency of pair cohesion (i.e. when the distance between partners was zero on a given day) was similar during the breeding (69.6%) and non-breeding seasons (67.7%). Breeding territories (kernel analysis) were 36.7 ± 5.7 ha and overlapped from year to year in all cases (23 pairwise comparisons; 47.9 ± 7.1% overlap). The high fidelity and constancy of territories confirms they warrant ongoing management investment, although the species relies on a matrix of breeding and non-breeding sites. The latter appear to occur in specific parts of the coast and warrant enhanced protection and more research attention. Fragmentation of the breeding population might occur where habitat is rendered unsuitable for > ~50 km.

The potential breeding range of Slender-billed Curlew Numenius tenuirostris identified from stable-isotope analysis

2017 ◽  
Vol 28 (2) ◽  
pp. 228-237
Author(s):  
GRAEME M. BUCHANAN ◽  
ALEXANDER L. BOND ◽  
NICOLA J. CROCKFORD ◽  
JOHANNES KAMP ◽  
JAMES W. PEARCE-HIGGINS ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Western Siberia ◽  
Isotope Analysis ◽  
Breeding Population ◽  
Calibration Equation ◽  
Breeding Sites ◽  
Breeding Range ◽  
Nest Sites ◽  
Nesting Sites ◽  
Southern Russia

SummaryThe breeding areas of the Critically Endangered Slender-billed Curlew Numenius tenuirostris are all but unknown, with the only well-substantiated breeding records being from the Omsk province, western Siberia. The identification of any remaining breeding population is of the highest priority for the conservation of any remnant population. If it is extinct, the reliable identification of former breeding sites may help determine the causes of the species’ decline, in order to learn wider conservation lessons. We used stable isotope values in feather samples from juvenile Slender-billed Curlews to identify potential breeding areas. Modelled precipitation δ2H data were compared to feather samples of surrogate species from within the potential breeding range, to produce a calibration equation. Application of this calibration to samples from 35 Slender-billed Curlew museum skins suggested they could have originated from the steppes of northern Kazakhstan and part of southern Russia between 48°N and 56°N. The core of this area was around 50°N, some way to the south of the confirmed nesting sites in the forest steppes. Surveys for the species might be better targeted at the Kazakh steppes, rather than around the historically recognised nest sites of southern Russia which might have been atypical for the species. We consider whether agricultural expansion in this area may have contributed to declines of the Slender-billed Curlew population.

Foraging ecology of the common dolphin Delphinus delphis revealed by stable isotope analysis

2020 ◽  
Vol 652 ◽  
pp. 173-186
Author(s):  
KJ Peters ◽  
SJ Bury ◽  
EL Betty ◽  
GJ Parra ◽  
G Tezanos-Pinto ◽  
...  
Keyword(s):  
New Zealand ◽  
Stable Isotope ◽  
Body Length ◽  
Stable Isotope Analysis ◽  
Foraging Ecology ◽  
Isotope Analysis ◽  
Minor Effect ◽  
Common Dolphin ◽  
Delphinus Delphis ◽  
Common Dolphins

Dolphins are among the largest and most diverse predators in marine ecosystems, but our understanding of their foraging ecology, which is crucial for ecosystem management, is poor. Delphinus delphis (common dolphins) are found in tropical and temperate waters globally. Stomach content studies indicate they are opportunistic predators that feed locally on abundant small pelagic schooling fish, but information is lacking on how their diet may vary seasonally and with ontogeny. We investigated effects of body length, sex, season, and year on D. delphis diet in the Hauraki Gulf, New Zealand, using carbon (δ13C) and nitrogen (δ15N) stable isotope analysis of 56 skin samples collected during 13 years (2004-2016). Dolphin δ15N values changed with body length, suggesting ontogenetic dietary variation. Nitrogen isotope values were higher in austral autumn/winter compared to spring/summer, whilst δ13C values decreased throughout the study period, suggesting temporal changes in primary productivity likely affecting the dolphins’ diet. Sex had a minor effect on dolphin δ13C values, with male and female isotopic niches overlapping by 62.6% and 45.2% (respectively). Our results provide a baseline for detecting future changes in the trophic ecology of D. delphis in a key habitat in New Zealand and highlight their role as a sentinel species in this coastal ecosystem.

scholarly journals Tipping back the balance: recolonization of the Macquarie Island isthmus by king penguins (Aptenodytes patagonicus) following extermination for human gain

2009 ◽  
Vol 21 (3) ◽  
pp. 237-241 ◽  
Author(s):  
John van den Hoff ◽  
Clive R. McMahon ◽  
Iain Field
Keyword(s):  
Breeding Season ◽  
Breeding Population ◽  
Egg Laying ◽  
King Penguin ◽  
Breeding Sites ◽  
Macquarie Island ◽  
Aptenodytes Patagonicus ◽  
Breeding Behaviour ◽  
Temporal Discontinuity

AbstractDuring the late 19th and early 20th centuries, when blubber oil fuelled house lamps, the king penguin population at Macquarie Island was reduced from two very large (perhaps hundreds of thousands of birds) colonies to about 3000 birds. One colony, located on the isthmus when the island was discovered in 1810, was extinct by 1894 and it took about 100 years for king penguins to re-establish a viable breeding population there. Here we document this recovery. The first eggs laid at Gadget Gully on the isthmus were recorded in late February 1995 but in subsequent years egg laying took place earlier between November and February (this temporal discontinuity is a consequence of king penguin breeding behaviour). The first chick was hatched in April 1995 but the first fledging was not raised until the following breeding season in October 1996. The colony increased on average 66% per annum in the five years between 1995 and 2000. King penguins appear resilient to catastrophic population reductions, and as the island's population increases, it is likely that other previously abandoned breeding sites will be reoccupied.

scholarly journals Subcolony Variation in Breeding Success in the Tufted Puffin (Fratercula Cirrhata): Association With Foraging Ecology and Implications

The Auk ◽  
2007 ◽  
Vol 124 (4) ◽  
pp. 1149-1157
Author(s):  
J. Mark Hipfner ◽  
Mathieu R. Charette ◽  
Gwylim S. Blackburn
Keyword(s):  
Stable Isotope ◽  
Breeding Success ◽  
Large Scale ◽  
Foraging Ecology ◽  
Isotope Analysis ◽  
Egg Yolk ◽  
Foraging Strategies ◽  
Small Scale ◽  
Carbon And Nitrogen ◽  
Tufted Puffin

Abstract Large-scale oceanographic processes are the main drivers of seabird breeding success, but small-scale processes, though not as well understood, can also be important. We compared the success of Tufted Puffins (Fratercula cirrhata) breeding at two subcolonies only 1.5 km apart on Triangle Island, British Columbia, Canada, 2002–2005. In addition, we used stable-isotope analysis to test the hypothesis that parental foraging strategies differed between the two subcolonies, potentially underlying the variation in breeding success. Success was concordant across years at the two sites but, overall, Tufted Puffins bred more successfully at Strata Rock than at Puffin Rock. They raised chicks in all four years at Strata Rock, but in only three years at Puffin Rock; in two of those three years, Strata Rock chicks were, on average, 60 g and 100 g heavier than Puffin Rock chicks just before fledging. Discriminant analysis of carbon and nitrogen stable-isotope ratios in egg yolk and chick blood in 2004 and 2005 indicated that parental foraging differed between the two subcolonies, with both spatial (δ13C) and trophic-level (δ15N) differences involved. Thus, our study demonstrates the existence of foraging asymmetries in a pelagic seabird at a small spatial scale (between subcolonies), complementing patterns found at larger scales (between colonies). Moreover, the foraging asymmetries were associated with inequalities in fitness measures. We conclude that small-scale processes—in this case, systematic differences in the foraging ecology of local groups—can interact with large-scale oceanographic processes to determine seabird breeding success. Variation sous-coloniale du succès de reproduction de Fratercula cirrhata: Association avec l'écologie de la quête alimentaire et implications

scholarly journals Awifauna wodno-błotna środkowej Wisły w okresie lęgowym: wpływ działalności człowieka na rozmieszczenie, liczebność i bogactwo gatunkowe

2011 ◽  
Vol 9 (2) ◽  
pp. 67-86 ◽  
Author(s):  
Dariusz Bukaciński ◽  
Monika Bukacińska ◽  
Arkadiusz Buczyński
Keyword(s):  
Bird Species ◽  
Natura 2000 ◽  
River Channel ◽  
River Valley ◽  
Breeding Bird ◽  
Breeding Sites ◽  
Vistula River ◽  
Breeding Habitats ◽  
Natura 2000 Site ◽  
River Bottom

The inventory of birds was conducted in the years 2005-2010 on the Vistula River section between Dęblin (388 km of the river) and Podwierzbie (435 km of the river). The study area includes a southern section of the European Ecological Natura 2000 Site in Poland PLB140004 „Middle Vistula River Valley” (IBA, PL083). In most areas the Vistula flows here within unregulated or relatively little modified riverbed, having features of natural, lowland, braided river. Sandy islands and braid bars within the main channel, steep banks, and old riparian afforestation create the unique breeding habitats of the Vistula River Valley. Especially the river channel habitats provide suitable breeding sites for many rare bird species, constituting some of them the key-breeding sites. There are, however, fragments of several kilometers, where people transformed the Vistula River in a more visible way (Table 1). These are, among others: an urban section within Dęblin boundaries (km 388-393 of the river), a fragment adjacent to Kozienice Power Plant (km 421-426), and the area, where since 2007 gravel for the industry has been mining from the river bottom (km 426-431). The aim of this inventory was the comparison of richness and abundance of breeding bird species associated directly with the river channel on fragments mentioned above. It will allow us to estimate soberly how very the intensity of human utilization of the river affects the distribution of avifauna of the Vistula, determining the richness and abundance of valuable and/or endangered species breeding in a given area.

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 Black Kite Milvus migrans in Slovenia – its distribution, phenology, breeding and habitat

Acrocephalus ◽  
2018 ◽  
Vol 39 (178-179) ◽  
pp. 71-83
Author(s):  
Dejan Bordjan
Keyword(s):  
Sea Level ◽  
Arable Land ◽  
Breeding Population ◽  
Water Bodies ◽  
Lower Percentage ◽  
Breeding Density ◽  
Breeding Sites ◽  
Milvus Migrans ◽  
Black Kite

Abstract Between 1984 and 2017, 1,388 Black Kites were recorded, mostly in lowlands with 70% of observations made at Dravsko polje. They were observed from sea level to around 1,600 m a.s.l. with an average elevation of 271 m a.s.l. The species was present in Slovenia from mid-March to early December with indistinct spring and autumn migrations. The highest number of observations was recorded in May. The Black Kite was observed in 71 out of 238 10x10 km grid squares in Slovenia (29.8%), with more observations around known breeding sites and at sites with higher observer effort. Both the number of observations and the number of probable and confirmed breeding pairs increased. In 2011–2018, 10 breeding pairs were found at 7 sites (3–7 per year). Additionally, 11 probable breeding pairs at 9 sites (0–6 pairs per year) were found. The breeding population in 2011–2018 is estimated at 10–21 pairs with an average breeding density of 0.3–0.9 breeding pairs per 100 km2. The highest density was recorded at Dravsko polje with 0.6–2.2 breeding pairs per 100 km2. If possible breeding (breeding attempts) were also taken into consideration, the estimate would be up to five breeding pairs higher. The species was recorded at known breeding sites in most years after the breeding was confirmed. Black Kites were observed closer to larger water bodies and to rubbish tips than expected by chance. More Black Kites were recorded in areas with a lower percentage of forest and arable land and a higher percentage of meadows, settlements and wetlands.

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