Caspian Tern

The Baja California Pacific Islands (BCPI) is a seabird hotspot in the southern California Current System supporting 129 seabird breeding populations of 23 species and over one million birds annually. These islands had a history of environmental degradation because of invasive alien species, human disturbance, and contaminants that caused the extirpation of 27 seabird populations. Most of the invasive mammals have been eradicated and colonies have been restored with social attraction techniques. We have recorded the number of breeding pairs annually for most of the colonies since 2008...

We investigated the cumulative effects of predation by piscivorous colonial waterbirds on the survival of multiple salmonid (Oncorhynchus spp.) populations listed under the U.S. Endangered Species Act (ESA) and determined what proportion of all sources of fish mortality (1 -survival) were due to birds in the Columbia River basin, USA. Anadromous juvenile salmonids (smolts) were exposed to predation by Caspian terns (Hydroprogne caspia), double-crested cormorants (Nannopterum auritum), California gulls (Larus californicus), and ring-billed gulls (L...

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While advances in biologging have revealed many spectacular animal migrations, it remains poorly understood how young animals learn to migrate. Even in social species, it is unclear how migratory skills are transmitted from one generation to another and what implications this may have. Here we show that in Caspian terns Hydroprogne caspia family groups, genetic and foster male parents carry the main responsibility for migrating with young. During migration, young birds stayed close to an adult at all times, with the bond dissipating on the wintering grounds...

High mortality in Caspian Terns (Hydroprogne caspia) and Great Black-headed Gulls (Larus ichthyaetus), was recorded on the northeastern shores of the Caspian Sea in June 2013. Retrospective high throughput sequencing of archived tissue samples conducted in 2018 revealed the presence of the recently identified novel gull adenovirus similar to that associated with mortality in gulls in the Netherlands in 2001. We suggest that that this gull adenovirus specifically can be considered as an emerging threat to the health and conservation of gulls and terns...

The degree to which predation is an additive versus compensatory source of mortality is fundamental to understanding the effects of predation on prey populations and evaluating the efficacy of predator management actions. In the Columbia River basin, USA, predation by Caspian terns (Hydroprogne caspia) on U.S. Endangered Species Act (ESA)-listed juvenile salmonids (smolts; Oncorhynchus spp.) has led to predator management actions to reduce predation; however, the assumption that reduced predation translates into greater salmonid survival, either within the life stage where predation occurs or across their lifetime, has remained untested...

Trematodes of the genus Galactosomum are cosmopolitan parasites that infect the intestines of fish-eating birds and mammals. Adults of named Galactosomum species have not been recorded from bird hosts in New Zealand, despite their cercarial stage being known from various studies of the first intermediate host, Zeacumantus subcarinatus. Here we describe a new species of Galactosomum infecting four different piscivorous birds in New Zealand: Caspian terns, red-billed and black-backed gulls and little blue penguins...

Seabirds are often cited as sentinels of the marine environment, but are rarely used in traditional ocean and coastal contaminant monitoring. Four classes of persistent organic pollutants (POPs, n=68) and three trace elements (mercury, selenium, and arsenic) were measured in the eggs of California least terns (Sterna antillarum browni), caspian terns (Hydroprogne caspia), double-crested cormorants (Phalacrocorax auritus), and western gulls (Larus occidentalis) that nest in the Southern California Bight. Building on a periodic five year regional monitoring program, we measured contaminant exposure and assessed the utility of seabirds as regional contaminant biomonitors...

A broad suite of 87 contaminants of emerging concern (CECs), including 26 polybrominated diphenyl ethers (PBDEs), 23 non-PBDEs halogenated FRs (NPHFRs), 16 organophosphate esters (OPEs), 4 perfluorinated sulfonates (PFSAs), 13 perfluorinated carboxylic acids (PFCAs) and 5 emerging perfluoroalkyl acids (PFAAs) or precursors, were determined in 30 individual Caspian tern (listed as a threatened species in the U.S. State of Michigan) eggs collected in 2013 and 2014 from Michigan nesting sites on Two Tree Island (St, Mary's River), Charity Reef (Saginaw Bay) and Channel-Shelter Island (a Confined Disposal Facility (CDF) in Saginaw Bay)...

Variation in avian bilateral symmetry can be an indicator of developmental instability in response to a variety of stressors, including environmental contaminants. The authors used composite measures of fluctuating asymmetry to examine the influence of mercury concentrations in 2 tissues on fluctuating asymmetry within 4 waterbird species. Fluctuating asymmetry increased with mercury concentrations in whole blood and breast feathers of Forster's terns (Sterna forsteri), a species with elevated mercury concentrations...

Migration patterns are believed to greatly influence concentrations of contaminants in birds due to accumulation in spatially and temporally distinct ecosystems. Two species of fish-eating birds, the Double-crested Cormorant (Phalacrocorax auritus) and the Caspian Tern (Hydroprogne caspia) breeding in Lake Ontario were chosen to measure the impact of overwintering location on mercury concentrations ([Hg]). We characterized (1) overwintering areas using stable isotopes of hydrogen (δ(2)H) and band recoveries, and (2) overwintering habitats by combining information from stable isotopes of sulfur (δ(34)S), carbon (δ(13)C), nitrogen (δ(15)N), and δ(2)H in feathers grown during the winter...

Many aquatic fish-eating birds migrate long distances and are exposed to different mercury concentrations ([Hg]) during their annual cycle. Here we examined the importance of migration on [Hg] in two colonial migratory fish-eating bird species. We determined temporal trends of [Hg] and stable isotopes of carbon (δ(13)C) and nitrogen (δ(15)N) during the annual cycle in Double-crested Cormorants (Phalacrocorax auritus) and Caspian Terns (Hydroprogne caspia) breeding in Lake Ontario by a repeated sampling of breast feathers and blood from recaptured individuals...

Understanding the biology and conducting effective conservation of migratory species requires an understanding of migratory connectivity - the geographic linkages of populations between stages of the annual cycle. Unfortunately, for most species, we are lacking such information. The North American Bird Banding Laboratory (BBL) houses an extensive database of marking, recaptures and recoveries, and such data could provide migratory connectivity information for many species. To date, however, few species have been analyzed for migratory connectivity largely because heterogeneous re-encounter probabilities make interpretation problematic...

We undertook breeding surveys between 2010 and 2011 to assess the status of breeding birds on 16 islands in the northern Saudi Arabia. Sixteen bird species were found breeding at three different seasons; i.e. winter (Osprey), spring (Caspian and Saunder's Terns), and summer (Lesser Crested, White-cheeked, Bridled Terns). It is postulated that food availability is an important factor influencing the breeding of seabirds in the northern Saudi Arabian Red Sea. Several species laid eggs earlier in northern parts of the Red Sea than in southern parts...

The Baku virus (BAKV) was originally isolated from the ticks Ornithodoros capensis Neumann, 1901 (Acari: Argasidae) collected from the seagull (Larus argentatus) seating nests on the islands of the Baku archipelago, the Caspian sea. BAKV was assigned to Kemerovo group (KEMV) (Orbivirus, Reoviridae). The BAKV was frequently isolated from the ticks O. coniceps Canestrini, 1980, collected from L. argentatus and tern (Sterna hirundo) nests in Turkmenia and pigeon (Columba livia neglecta) nests in Uzbekistan. In this work, the genome of the BAKV was sequenced using the next-generation sequencing technology...

Mercury levels were measured in colonial waterbird eggs collected from two sites in northern Alberta and one site in southern Alberta, Canada. Northern sites in the Peace-Athabasca Delta and Lake Athabasca were located in receiving waters of the Athabasca River which drains the oil sands industrial region north of Fort McMurray, Alberta. Temporal trends in egg mercury (Hg) levels were assessed as were egg stable nitrogen isotope values as an indicator of dietary change. In northern Alberta, California and Ring-billed Gulls exhibited statistically significant increases in egg Hg concentrations in 2012 compared to data from the earliest year of sampling...

Lethal control, which has been used to reduce local abundances of animals in conflict with humans or with endangered species, may not achieve management goals if animal movement is not considered. In populations with emigration and immigration, lethal control may induce compensatory immigration, if the source of attraction remains unchanged. Within the Columbia River Basin (Washington, U.S.A.), avian predators forage at dams because dams tend to reduce rates of emigration of juvenile salmonids (Oncorhynchus spp...

Ultraviolet-sensitive vision (UVS), believed to have evolved from an ancestral state of violet-sensitive vision (VS), is widespread among terrestrial birds, where it is thought to play a role in orientation, foraging, and sexual selection. Less is known, however, about the distribution and significance of UVS in seabirds. To date UVS has been definitively demonstrated only in two families (Laridae and Sternidae), although indirect evidence has been used to argue for a more widespread occurrence. In this study we analyzed short-wavelength sensitive (SWS1) opsin DNA sequences to determine the distribution of ancestral (VS) and derived (UVS) amino acid spectral tuning sites in 16 seabird species representing 8 families with diverse ecological niches...

Bioindicators of oxidative stress were examined in prebreeding and breeding adult and chick Forster's terns (Sterna forsteri) and in prebreeding adult Caspian terns (Hydroprogne caspia) in San Francisco Bay, California. Highest total mercury (THg) concentrations (mean ± standard error; µg/g dry wt) in liver (17.7 ± 1.7), kidney (20.5 ± 1.9), and brain (3.0 ± 0.3) occurred in breeding adult Forster's terns. The THg concentrations in liver were significantly correlated with hepatic depletion of reduced glutathione (GSH), increased oxidized glutathione (GSSG):GSH ratio, and decreased hepatic gamma-glutamyl transferase (GGT) activity in adults of both tern species...

Mercury content of egg and eggshell from Whiskered Terns of Anzali wetlands of the Caspian Sea were determined. Mercury levels in egg content of both abandoned (433 ± 4) and non-abandoned (459 ± 15) eggs were 150 times greater than eggshells. Eggshell thickness differed between non-abandoned (0.5 ± 0.03) and abandoned eggs (0.6 ± 0.5) (p < 0.001). No significant association was found between shell Hg and shell thickness in this study. There was significantly more Hg in egg content than in shell (p < 0...