Synthliboramphus Antiquus Research Articles

CAPTURE RATES OF NORWAY RATS (RATTUS NORVEGICUS) IN A SEABIRD COLONY: A CAVEAT FOR INVESTIGATORS

Abstract The introduction of rat species (Rattus spp.) is a conservation concern for island avifauna throughout the world. I employed 3 commonly used monitoring techniques for rats: live-trapping, snap-trapping, and apples as indicator baits at several sites on Langara Island, British Columbia, with and without the presence of breeding seabirds. Capture rates of Norway rats (Rattus norvegicus) in snap traps in an ancient murrelet (Synthliboramphus antiquus) colony while murrelets were actively breeding ranged between 0.0 and 0.7 captures per 100 trap-nights (C/100 TN), while concurrent capture rates in other regions of the island outside of the ancient murrelet colony ranged from 2.2 to 17.1 C/100 TN. Live traps in the ancient murrelet colony also had low capture rates (0 to 0.5 C/100 TN) while murrelets were present in the colony. Once murrelets departed following their breeding, capture rates in snap traps in the ancient murrelet colony rose to 9.9 to 14.0 C/100TN, rates comparable to other areas of the...

Influence of Chick Mass and Date at Departure from the Colony on Adult Characteristics in Ancient Murrelets (Synthliboramphus Antiquus), A Precocial Seabird

Abstract I investigated the effect of mass and date of departure of Ancient Murrelet (Synthliboramphus antiquus) chicks reared at two colonies in Haida Gwaii, British Columbia, on aspects of their adult biology. Chicks were captured, banded, and weighed while departing from their natal colony at two to three days old, during 1984–1998. Adults were recaptured at the same colonies during the breeding seasons of 1986–2000. Just under 1% of 13,055 chicks were recaptured as adults. Chicks that were heavier than average at colony departure were recaptured as adults at a younger age and were heavier as breeders than lighter chicks. However, chick departure mass did not affect adult mass of birds recaptured as nonbreeders. The date at which chicks left the colony had no effect on either adult mass or age at recapture. Correlation between chick mass at colony departure and adult mass as a breeder is rarely reported and is difficult to explain. However, if chick mass is determined by reproductive investment on the part of the parents and adult mass is a measure of reproductive investment by the individual, the correlation suggests that degree of parental investment could be a heritable trait.

Influence of Chick Mass and Date at Departure from the Colony on Adult Characteristics in Ancient Murrelets (Synthliboramphus antiquus), a Precocial Seabird

Influence of Chick Mass and Date at Departure from the Colony on Adult Characteristics in Ancient Murrelets (Synthliboramphus antiquus), a Precocial Seabird

INFLUENCE OF CHICK MASS AND DATE AT DEPARTURE FROM THE COLONY ON ADULT CHARACTERISTICS IN ANCIENT MURRELETS (SYNTHLIBORAMPHUS ANTIQUUS), A PRECOCIAL SEABIRD

Abstract I investigated the effect of mass and date of departure of Ancient Murrelet (Synthliboramphus antiquus) chicks reared at two colonies in Haida Gwaii, British Columbia, on aspects of their adult biology. Chicks were captured, banded, and weighed while departing from their natal colony at two to three days old, during 1984–1998. Adults were recaptured at the same colonies during the breeding seasons of 1986–2000. Just under 1% of 13,055 chicks were recaptured as adults. Chicks that were heavier than average at colony departure were recaptured as adults at a younger age and were heavier as breeders than lighter chicks. However, chick departure mass did not affect adult mass of birds recaptured as nonbreeders. The date at which chicks left the colony had no effect on either adult mass or age at recapture. Correlation between chick mass at colony departure and adult mass as a breeder is rarely reported and is difficult to explain. However, if chick mass is determined by reproductive investment on the ...

Foraging Behavior and Resource Partitioning by Diving Birds During Winter in Areas of Strong Tidal Currents

Abstract We investigated the distribution and behavior of 21 species of diving birds wintering in tidally active nearshore ocean off southern Vancouver Island, British Columbia, Canada. Using vessel surveys in one site and land-based observations at a second site, we found significant differences in the use of tidally affected water types among and within three foraging guilds (piscivores, plankton feeders and benthic invertebrate predators) and five families (Gaviidae, Podicipedidae, Phalacrocoracidae, Anatidae, Alcidae). The only abundant plankton feeder, Ancient Murrelets (Synthliboramphus antiquus), foraged more frequently than other birds in areas of deeper water (>10 m) with fast tidal flow and turbulence. Their abundance and diving activity were significantly higher at maximum tide flow than at slack tides. Piscivores used both slack water and moderate currents in a wide range of depths but, apart from alcids and Pelagic Cormorants (Phalacrocorax pelagicus), avoided areas of high current and turbul...

Mitochondrial DNA Suggests High Gene Flow in Ancient Murrelets

AbstractAncient Murrelets (Synthliboramphus antiquus) are subarctic seabirds that breed on islands from British Columbia through Alaska to China. In this study, we used sequence variation in the mitochondrial control region and cytochrome b gene to estimate the extent of genetic differentiation and gene flow among populations both within British Columbia and across the North Pacific. Results suggest that genetic differentiation is low and female-mediated gene flow is high among colonies within British Columbia, in agreement with banding studies. Surprisingly, genetic differentiation appears to be low and gene flow high between British Columbia and Asia. The effective female population size appears to be stable, but the species may have undergone a range expansion. These results suggest that Ancient Murrelets from throughout the North Pacific may represent a single management unit for conservation.El ADN Mitocondrial Sugiere Alto Flujo Génico en Synthliboramphus antiquusResumen. Synthliboramphus antiquus es una especie de ave marina subártica que se reproduce en islas desde British Columbia a través de Alaska hasta China. En este estudio estimamos el grado de diferenciación genética y de flujo génico entre poblaciones localizadas dentro de British Columbia y a través del Pacífico Norte. Nos basamos en la variación en secuencias de la región control y el gen citocromo b del ADN mitocondrial. Los resultados sugieren baja diferenciación genética y alto flujo génico mediado por las hembras entre las colonias de British Columbia, lo que es consistente con estudios de aves anilladas. Sorprendentemente, la diferenciación genética parece ser baja y el flujo génico alto entre British Columbia y Asia. El tamaño efectivo de la población de hembras parece estar estable, pero la especie podría haber expandido su rango de distribución. Estos resultados sugieren que los S. antiquus de todo el Pacífico Norte pueden representar una sola unidad de manejo en términos de conservación.

MITOCHONDRIAL DNA SUGGESTS HIGH GENE FLOW IN ANCIENT MURRELETS

Abstract Ancient Murrelets (Synthliboramphus antiquus) are subarctic seabirds that breed on islands from British Columbia through Alaska to China. In this study, we used sequence variation in the mitochondrial control region and cytochrome b gene to estimate the extent of genetic differentiation and gene flow among populations both within British Columbia and across the North Pacific. Results suggest that genetic differentiation is low and female-mediated gene flow is high among colonies within British Columbia, in agreement with banding studies. Surprisingly, genetic differentiation appears to be low and gene flow high between British Columbia and Asia. The effective female population size appears to be stable, but the species may have undergone a range expansion. These results suggest that Ancient Murrelets from throughout the North Pacific may represent a single management unit for conservation. El ADN Mitocondrial Sugiere Alto Flujo Genico en Synthliboramphus antiquus Resumen. Synthliboramphus antiquu...

Status of Seabirds Breeding in Hokkaido.

The historic and present status of seabirds in Hokkaido is summarized, based on published and unpublished data. At least 12 species breed in Hokkaido. The breeding pairs of seabirds in recent years in Hokkaido are estimated as follows: Common Murre (Uria aalge) <10; Tufted Puffin (Lunda cirrhata) 15; Spectacled Guillemot (Cepphus carbo) 100; Ancient Murrelet (Synthliboramphus antiquus) <20; Rhinoceros Auklet (Cerorhinca monocerata) 300, 000; Slaty-backed Gull (Larus schistisagus) 10, 000; Black-tailed Gull (Larus crassirostris) 30, 000; Red-faced Cormorant (Phalacrocorax urile) 25; Japanese Cormorant (Phalacrocorax capillatus) 3, 000; Pelagic Cormorant (Phalacrocorax pelagicus) 10; Streaked Shearwater (Calonectris leucomelas) 120; Leach's Stormpetrel (Oceanodroma leucorhoa) 900, 000. The present status of the Long-billed Murrelet (Brachyramphus perdix) is unclear. The colony size of Common Murre shrank with annual decreasing rate of 12.2% (1938-80)-26.6% (1981-94) on Teuri Island. It has decreased 24.8% annually, and it has not been observed on Moyururi Island since 1985. The Tufted Puffin and Spectacled Guillemot decreased 9-15% annually during the last 30 years. The Slaty-backed Gull increased 11.0% annually (1963-95) on Teuri Island, and 8.5% annually (1972-93) on Yururi Island. Black-tailed Gull increased by 5% annually (1987-2000) on Rishiri Island, but decreased on Teuri Island during the 1990's. The Japanese Cormorants increased by 5-9% annually on Teuri and Yururi Islands. Its number increased at annual rate of 6.4% during 1959-86, but decreased at annual rate of 10.4% during 1987-96 on Moyururi Island. At 12 of the 14 surveyed colonies predation by gulls and/or crows were reported, and disturbances caused by introduced rats and cats was reported at five colonies. Although most of the colonies are legally protected, few conservation programs have been effectively conducted. Seabird mortality by fishing nets was reported around six colonies, but protective measure for seabirds has not been taken. We here propose, therefore, non-fishing sea areas for seabird protection around such breeding islands.

Specimen records and sightings of ancient murrelets from the Canadian Prairie Provinces

Specimen records and sightings of ancient murrelets from the Canadian Prairie Provinces

Specimen records and sightings of ancient murrelets from the Canadian Prairie Provinces

Specimen records and sightings of ancient murrelets from the Canadian Prairie Provinces

Changes in oceanographic conditions off northern British Columbia (1983–1999) and the reproduction of a marine bird, the Ancient Murrelet (Synthliboramphus antiquus)

We examined variation in breeding-biology parameters for Ancient Murrelets (Synthliboramphus antiquus), marine birds breeding in central Hecate Strait, British Columbia, over the period 1983–1999. Interannual changes were compared with physical oceanographic data (sea-surface temperatures (SSTs) and Southern Oscillation (SO) indices) for surrounding waters. No secular change in oceanographic data for Hecate Strait was detectable for the period considered, which embraced two major (1982–1983, 1997–1998) and three minor El Niño – Southern Oscillation (ENSO) events. SSTs were strongly related to the SO index for the area considered. Breeding-biology data were not available for the 1982–1983 ENSO. The 1997–1998 ENSO had a strong effect on breeding success, reducing the number of chicks per pair from &gt;1.4 to below 1; most of this effect was caused by desertions before incubation began. We found a positive correlation between May SST and the slope of the regression of chick mass at colony departure on a particular date for a given year. This effect may have resulted from the failure of young or otherwise less competent birds to rear young in years of high SSTs. Both the median date of colony departure and chick mass at departure declined over the period of the study, although neither effect was related to changes in the oceanographic variables considered in this study. These trends may relate to longer term changes in oceanographic conditions in the North Pacific Ocean. If they continue, the recent trend towards lower chick masses at colony departure may have adverse effects on recruitment and eventually on Ancient Murrelet populations.

Changes in oceanographic conditions off northern British Columbia (1983–1999) and the reproduction of a marine bird, the Ancient Murrelet (&lt;i&gt;Synthliboramphus antiquus&lt;/i&gt;)

Changes in oceanographic conditions off northern British Columbia (1983–1999) and the reproduction of a marine bird, the Ancient Murrelet (&lt;i&gt;Synthliboramphus antiquus&lt;/i&gt;)

Eradication of Norway Rats for Recovery of Seabird Habitat on Langara Island, British Columbia

AbstractIntroduced Rattus norvegicus (Norway rats) caused the decline of Synthliboramphus antiquus (ancient murrelets) and other seabirds breeding on Langara Island (approximately 3,100 ha), British Columbia. Using funds from the litigation settlement following the Nestucca oil spill, Environment Canada eradicated Norway rats using a technique developed in New Zealand which involved dispensing wax baits containing the anticoagulant brodifacoum at 50 ppm from fixed bait stations. Bait stations were placed every 75 to 100 m on a grid over the entire island (1 station/ha). Rats removed bait for 26 days, after which crews placed baits in protective plastic bags in each bait station. Stations loaded with baits were left on the island and rechecked four times over 2 years, after which bait stations and remaining bait were removed. The eradication succeeded. No signs of rats have been detected on Langara Island and its associated islands since January 1996. No rats were trapped during 1,700 trap‐nights following the poison campaign. Incisor marks of rats were not found on apples or oil‐dipped chew‐sticks. Corvus corax (common ravens) likely suffered greater than 50% mortality from the eradication after apparently gaining access to the poison directly from bait stations and from scavenging rat carcasses. A monitoring and response system is being developed in conjunction with current users of the islands. The success on Langara Island demonstrates how the technique proven on small New Zealand islands of less than 300 ha can be effectively extrapolated to much larger islands.

Norway Rats as Predators of Burrow-Nesting Seabirds: Insights from Stable Isotope Analyses

Introduced species to oceanic islands can cause tremendous declines and extinctions of native avifauna. On Langara Island. British Columbia, Canada, the burrow-nesting ancient murrelet (Synthliboramphus antiquus) has declined from all estimated original population of 200,000 pairs to 14,600 pairs ill 1993. Previously, causes of this decline were unknown, but the introduction of Norway rats (Rattus norvegicus) has been implicated as a major factor and has resulted in a recent rat eradication program. A major obstacle in the investigation of the effects of rats on seabirds, here and elsewhere, has been the inability to accurately assess the importance of seabirds to the diets of rats that also consume a variety of plants and invertebrates. We used stable-carbon (δ 13 C), nitrogen (δ 15 N), and sulphur (δ 34 S) isotope analyses of muscle and liver tissues of rats and prey organisms from 3 regions of Langara Island to evaluate evidence for marine foods, including seabirds, in the diets of rats. Rats were segregated into 3 isotopic groups corresponding to upland, littoral, and seabird nesting areas on the island. We interpret these groups to represent individuals consuming predominantly C-3 terrestrial foods (x δ 15 N = 5.4‰; x δ 13 C = -24.9‰; n = 24), intertidal invertebrates (x δ 15 N = 8.9‰; x δ 13 C = -14.3‰; n = 21), and ancient murrelet adults, chicks, or eggs (x egg δ 15 N = 13.2‰; x δ 13 C = -17.6‰; n = 8). We found strong correlations between liver and muscle isotope values for both 13 C and 15 N, suggesting that dietary preferences within individuals remained relatively constant. Stable-sulphur isotope values of rat liver were less useful in segregating marine and terrestrial dietary inputs, possibly because sources of sulphur to tile terrestrial food web were of marine origin pooled x δ 34 S value = 17.8‰; n = 20). Our measurement of liver and muscle tissues gave dietary estimates based on relatively short- and long-tern integrations and revealed tile 3 groups of rats remained isotopically segregated at least over the 2-month period of ancient murrelet breeding on Langara Island. Our results have important ramifications for dietary investigations of introduced fauna and their effect on native scabirds on oceanic slands.

Brodifacoum Poisoning of Avian Scavengers During Rat Control on a Seabird Colony

Langara Island, at the north-western tip of British Columbia's Queen Charlotte archipelago, was once nesting grounds for an estimated 500,000 seabirds. However, infestations of Norway rats (Rattus norvegicus) and their predation of eggs and breeding adults have caused extirpation or serious declines of all seabird species. By 1993, the breeding population of ancient murrelets (Synthliboramphus antiquus) had declined to 10% of its historical size. Successful eradication of rats on smaller New Zealand islands using the anticoagulant brodifacoum prompted its application on Langara Island. The island is also home to breeding bald eagles (Haliaeetus leucocephalus), peregrine falcons (Falco peregrinus), and other wildlife. No comprehensive studies of non-target impacts and potential for secondary poisoning were done during similar operations elsewhere; thus, in 1994 and 1995 we initiated a two-year study into the risk of secondary poisoning to non-target species. During 1994, rat carcasses were laid out with motion sensor cameras to identify potential scavengers. Ravens, northwestern crows and bald eagles were photographed at carcasses, and therefore at risk of feeding on rats that die above ground. During the baiting program, 19 rats were radio-tagged to determine the proportion dying above ground, and thus available to predators/scavengers. Ravens were found poisoned both from feeding directly on the bait, and predating/scavenging poisoned rats. Bald eagles were trapped and blood sampled for brodifacoum residue analysis and prothrombin time evaluation; 15% of the sampled population showed detectable residues but no adversely-affected birds were found. We conclude that the use of brodifacoum for rat removal on seabird islands poses a clear risk of secondary poisoning to avian scavengers. This risk must be weighed against the benefit of rat removal programs.

Histological observations on some visceral organs of an oil-polluted ancient murrelet synthliboramphus antiquus (aves) stranded on the Niigata coast

Histological observations on some visceral organs of an oil-polluted ancient murrelet synthliboramphus antiquus (aves) stranded on the Niigata coast

Heavy metal and metallothionein concentrations in seabirds from the Pacific coast of Canada

Seabird tissues, collected during the 1990 breeding season from colonies on the Pacific coast of Canada, were analysed for Cd, Hg, Pb and 19 other trace elements. Metallothionein (Mt) was measured in kidneys of three species. Ranges of essential trace metal concentrations were generally narrow, consistent with homeostatic control of these elements in seabird tissues. Cadmium concentrations were always higher in kidney than in liver. Highest mean Cd concentrations (306±78 μg g −1 dry wt) were in kidneys of planktivorous Leach's storm-petrels ( Oceanodroma leucorhoa) from Hippa Island in the Queen Charlotte archipelago. Cadmium concentrations in kidneys of both Leach's storm-petrels and rhinoceros auklets ( Cerorhinca monocerata) were significantly greater at northern colonies compared to those further south. Cadmium and Mt concentrations were positively correlated in kidneys across the three species for which measurements were made [rhinoceros auklet, Cassin's auklet ( Ptychoramphus aleuticus), and ancient murrelet ( Synthliboramphus antiquus)] with an overall r = 0.82, p < 0.001. Mercury accumulation was not sufficiently great to be of toxicological concern in any of the 5 species. Highest mean Hg concentrations (6.37 μg g −1) were in livers of Leach's storm-petrels from Cleland Island on the west coast of Vancouver Island, and were significantly greater than in birds from further north on Hippa Island. Concentrations of hepatic Hg and Se were not correlated in the three species (rhinoceros auklet, Cassin's auklet and ancient murrelet) for which Se was measured. Lead concentrations were consistently greatest in bone, with highest mean concentrations in fork-tailed storm-petrels ( Oceanodroma furcata) (6.2 μg g −1 dry wt).

Effects of the Exxon Valdez Oil Spill on Habitat Use by Birds along the Kenai Peninsula, Alaska

We examined habitat use by 34 species of marine-oriented birds along the Kenai Peninsula, Alaska, in 1989-1991 to measure effects of the Exxon Valdez oil spill of March 1989 outside of the immediate spill area in Prince William Sound. Overall, 22 species (65%) did not exhibit statistically significant initial negative impacts on their use of oil-affected habitats. Of the 12 species that did exhibit significant negative impacts on habitat use, 6 showed evidence of recovery by the end of the study in late 1991. Of the 6 species that failed to show clear evidence of recovery, two (Common Merganser and Glaucous-winged Gull) showed no evidence of recovery by 1991, three (Common Loon, Double-crested Cormorant, and Sharp-shinned Hawk) may have begun recovery by 1991, and evaluation of recovery of the sixth species (Ancient Murrelet) was precluded by a lack of data. On individual surveys, the proportion of species recorded that exhibited negative impacts declined through time, from 36% on the first survey after the spill in 1989 to 19% in late 1991. These results indicate that the Exxon Valdez oil spill had significant initial effects on habitat use by some marine-oriented birds along the Kenai, although the majority of species analyzed showed no obvious spill-related effects on habitat use and impacts on several other species were not prolonged.

Raccoon Predation on Ancient Murrelets on East Limestone Island, British Columbia

We evaluated the threat posed by introduced raccoons (Procyon lotor) to native, burrow-nesting seabirds of the Queen Charlotte Islands, British Columbia. In 1991, we described and quantified raccoon predation within a 14.9-ha colony of about 1,200 pairs of ancient murrelets (Synthliboramphus antiquus). An estimated 3-4 raccoons were present on the island. We obtained radiolocations and sightings for one female and one male throughout the seabird breeding season, and investigated these locations for evidence of predatory activity. Eleven of 15 such investigations led to fresh evidence of predation on ancient murrelets, such as dug burrows, broken eggs, and one or more decapitated adults, suggesting that raccoons were responsible for these types of predation sign. We estimated predation from all sources within the seabird colony by conducting transect surveys. These covered about 17% of the colony area, and were carried out every third afternoon from 8 April to 8 June. Twenty-one surveys yielded 6 headless carcasses, 77 feather piles, 30 broken eggs, 2 dead chicks, and 20 dug burrows, representing an estimated loss of 488 ± 110 adult and subadult birds, and 188 ± 102 eggs and chicks within the colony (95% CL). Estimates of raccoon predation based on the number of headless carcasses and diggings found on transects were 35 ± 35 and 71 ± 42, however, these are considered underestimates because they do not account for the rapid conversion of seabird carcasses by avian scavengers, or the capture of birds aboveground. Monitoring of seabird remains indicated that about 92% (n = 38) of headless carcasses were consumed or converted to feather piles by avian scavengers within <3 days, indicating that the number of carcasses found on predation transect surveys could underestimate raccoon predation by as much as an order of magnitude. The suggestion that raccoons were responsible for most seabird losses is supported by changes in the level of predation recorded between years. Predation levels were similar in 1990 and 1991, in the presence of raccoons, and declined by 80% in 1992, following the removal of raccoons. Raccoon predation represents a conservation threat of international significance, because the Queen Charlotte Islands contain the majority of the world's ancient murrelet population, as well as substantial populations of several other burrow-nesting species that are also susceptible to raccoon predation.

A Nest Box for Ancient Murrelets

A Nest Box for Ancient Murrelets