Paired throat and cloacal swabs, along with feather samples, from nesting Double-crested Cormorants (Phalacrocorax auritus) at two sites in Illinois, USA, were tested for presence of invasive ...bigheaded carp (Hypophthalmichthys spp.) DNA. We also used DNA from the feather calamus to determine cormorant sex. Throat and cloacal swabs from cormorants at both locations tested positive for DNA from silver carp (H. molitrix), but none tested positive for bighead carp (H. nobilis). Hypophthalmichthys DNA was not detected on feathers. There were no significant differences among positive Hypophthalmichthys DNA detection frequencies between cormorant sexes. To our knowledge, this is the first demonstration of silver carp as part of the Double-crested Cormorant diet in North America. Hypophthalmichthys are major invasive species of concern in this region, the detection of water-borne environmental DNA of Hypophthalmichthys is an important monitoring tool, and the potential movement of DNA via piscivorous birds may have significant implications for interpreting environmental DNA monitoring data.
The coastal waters of southern British Columbia, Canada, encompass habitat of international conservation significance to coastal and marine birds, including sizeable areas designated in the early ...1900s as Migratory Bird Sanctuaries (MBS) to protect overwintering waterfowl from hunting near urban centres. Two of these, Shoal Harbour (SHMBS) and Victoria Harbour (VHMBS), have seen significant marine infrastructure development in recent decades and experience considerable vessel traffic. Vessel-related stressors are known to affect waterbirds, but traffic characteristics in coastal urban areas are poorly understood for the smaller vessels not tracked by Automatic Identification Systems (AIS). We conducted a pilot study using shore-based observers to develop small-vessel baselines for the winter months, when regional waterbird numbers are highest. During our surveys we recorded considerable inter-site variability in vessel traffic characteristics, with one site (SHMBS) a source of nearly twice as many vessel transits as the other (VHMBS). Most recorded vessels were small watercraft (mean length 26 ± 17', mode 18'), and vessels at the high-traffic site were both shorter and faster on average. One in six vessels were classified as 'noisy', of interest given that noise is an important component of vessel disturbance of waterbirds and other marine animals. Few vessels (7% of all recorded) were of the type required to carry AIS transponders, which highlights the monitoring gap created by using AIS-based approaches alone in nearshore waters, and allows for correction of AIS-derived vessel counts. Waterbird community composition also varied by locality, with one site dominated by gulls (Laridae), cormorants (Phalacrocoracidae), and seaducks (Tribe Mergini), and the other by gulls, cormorants, and alcids (Alcidae). Our results demonstrate that fine-scale local variability must be taken into account when managing for vessel traffic disturbance of waterbirds, particularly at sites of high human population density and increasing coastal development.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The anthropause during the recent COVID-19 pandemic provided a unique opportunity to examine the impact of human activity on seabirds. Lockdowns in Peru prevented people from visiting coastal areas, ...thereby reducing garbage disposal on beaches and the movement of microplastics into the ocean. This cessation of activities likely led to a temporary decrease in plastic pollution in coastal regions. We aimed to investigate this phenomenon in inshore-feeding neotropic cormorants (
) along the Circuito de Playas Costa Verde (CPCV), situated on the coastal strip of Lima, Peru (∼ 11 million people).
We collected and analyzed fresh pellets along the CPCV before (over 11 months) and during the pandemic lockdowns (over 8 months).
Our findings revealed a significant reduction in the occurrence of plastic in pellets during the pandemic period (% Oc = 2.47,
= 647 pellets) compared to pre-pandemic conditions (% Oc = 7.13,
= 800 pellets). The most common plastic debris item found in the pellets was threadlike microplastic. Additionally, our study highlights the direct correlation between human presence on beaches and the quantity of microplastics (mainly threadlike) found in cormorant pellets. We suggest that the reintroduction of these materials into the sea, previously accumulated on the coast, is likely facilitated by the movement and activity of beachgoers toward the ocean.
Plasma biochemistries provide a complementary method for assessing physiological and nutritional status of free-ranging wild birds. Triglycerides, total protein and alkaline phosphatase were ...determined in 110 free-living Imperial Cormorant (Phalacrocorax atriceps) chicks aged 16-35 days, at Punta León (Argentina) during 2010 and 2011. Body mass at 30 days of age (“pre-fledging body condition”, 2010 only) and body mass corrected by tarsus length at the time of blood sampling (“current body condition”, 2011 only) were also determined. Variability of parameters by sex, hatching order, survival, age and breeding season was assessed, and the relationship between biochemical and morphometric indices was also explored. Morphometric indices were higher in A-chicks (pre-fledging body condition also varied with sex), and explained 35-55% of B-chick survival. Biochemistries differed significantly between breeding seasons, being higher in 2011. Alkaline phosphatase increased with age, and total protein was higher in A-chicks. Triglycerides and total protein accounted for 26% and 30%, respectively, of variation in current body condition; however, they did not forecast pre-fledging body condition. Lastly, total protein levels predicted B-chick survival (higher levels in surviving B-chicks), but their prognostic value was relatively low. The results suggest that unlike morphometric indices, the biochemistries chosen are valuable to assess individual body condition at the time of sampling, yet their applicability for predicting chick survival requires further evaluation.
We describe species richness of birds, especially North American ardeids, from Crooked Tree Lagoon, northern Belize. We recorded 62 species, 27 families, and 33 species of migrants. The dominant ...species include limpkin (Aramus guarauna), Neotropic cormorant (Nannopterum brasilianum), great egret (Ardea alba), and snail kite (Rostrhamus sociabilis). By macrohabitat, 38 species (61%) are primarily aquatic, 17 (27%) primarily terrestrial, and 7 (11%) transitional. Ardeids are a species-rich family, with 13 of the 16 species of North American herons and egrets represented; the dominant species are great egret and great blue heron (A. herodias). We discuss explanations for the diversity observed, as well as reasons for the absence of three species. This reserve is important not only for ardeids and aquatic species but also many migrant land birds.
Ten of the 15 seabird species that breed in the Benguela upwelling ecosystem, including six species that are endemic to it, are now classified as threatened or near-threatened in terms of Red List ...criteria. Both bottom-up (operating from lower in the food chain) and top-down (operating from higher in the food chain, or outside it) processes have influenced the seabirds. Historical harvests of eggs and guano caused a large decrease in numbers of African penguins Spheniscus demersus and altered their breeding habitat. More recently, food scarcity reduced the populations of several species that compete with fisheries for prey and was largely responsible for the recent collapse of penguins in South Africa. Predation, oiling and disturbance also have adversely affected seabirds and their relative impact may increase as species populations and sizes of colonies decrease. Co-ordinated management of the different factors diminishing populations will be necessary if the conservation status of seabirds in the Benguela ecosystem is to be improved.
•Fifteen species of seabird breed in the Benguela ecosystem off southwestern Africa, of which seven are endemic to it and two more are endemic as races. Six of the endemic species have an unfavourable Red List classification.•The paper reviews bottom-up and top-down control of the Benguela's seabirds and shows that while top-down factors (including exploitation of seabirds and their products) were responsible for earlier large decreases of some species, recently food scarcity (bottom-up control) has caused big decreases of some species that compete with fisheries for prey.•Species breeding on the mainland are susceptible to human disturbance (top-down control).•For seabirds whose populations and colony sizes are decreasing the relative importance of top-down factors is likely to increase, so that coordinated management of all the threats to these species will be required to improve their conservation status.
Clinostomum
Leidy, 1856 (Trematoda: Clinostomidae) is a cosmopolitan, zoonotic genus of fluke that has been poorly studied in an Australian setting. Following previous reports of reservoir fish in ...Australian fish ponds being heavily infected with
Clinostomum
metacercaria, the current study was conducted to determine the specific identity of
Clinostomum
sp. in inland Australia, by examining and characterizing parasites collected from a potential definitive host, cormorants. A total of 33 parasite specimens belonging to the genus
Clinostomum
were collected from two cormorants (little black cormorants,
Phalacrocorax sulcirostris
) that were collected from the Narrandera Fisheries Research Centre, New South Wales, at the same locality where metacercaria of
Clinostomum
sp. have been reported in fish. All specimens in our study were immature adults.
Clinostomum
specimens with similar morphology have been identified as
C. complanatum
in the past, based on their morphological characteristics. However, phylogenetic analyses based on the ITS sequence data in the present study suggest they are the same as the
Clinostomum
sp. previously reported from carp gudgeons (
Hypseleotris
spp.) from the same farm, and distinct from
C. complanatum
. The ITS sequences obtained from the specimens in the present study were most similar to those belonging to
C. phalacrocoracis
(never reported in Australia). Our specimens formed a distinct clade on the phylogenetic tree and their specific identity awaits until fully mature specimens are described in future studies.
Aim of study: To investigate the impact of allochthonous material from piscivorous birds on forest soil microarthropod communities. Area of study: Six study zones in the Curonian Spit peninsula ...(western Lithuania) were designated in Pinus sylvestris stands with nesting sites of the great cormorants, taking into account the relief and the duration of the ornithogenic impact. Materials and methods: The total abundance of mites and Collembola and the species richness and diversity of Oribatida and Gamasina mites were assessed and compared. Main results: The abundance of Collembola, Tarsonemidae and Acaridae mites positively correlated with ornithogenic activity, while Oribatida and Gamasina mites decreased significantly. The structure of microarthropod communities was similar in most of the studied zones, except for the active nesting zone and the abandoned part of the colony on the dune slope. The greatest species richness of Oribatida and Gamasina was found in the unaffected forest in the dune hollow, whereas the lowest value was found in the active nesting area and in the abandoned part of the colony on the dune slope. Of the environmental parameters studied, soil pH (r = - 0.725) and tree layer (r = 0.827) were those most significantly related to the changes of microarthropod communities. Research highlights: We found that cormorant colonies have a strong impact on forest ecosystems and soil properties, leading to significant changes in soil microarthropod communities. Birds thus create a natural disturbance experiment that can help reveal the factors that determine the diversity and composition of natural microarthropod communities.
Following decades of global extermination, the general population of the great cormorant (Phalacrocorax carbo L.) is on the rise. The lack of regular predators, highly skilled fish rapacity, rapid ...metabolism, significant rate of excretion and ability to form large nesting colonies on relatively small areas lead to numerous environmental consequences of cormorant presence. Here we comprehensively review the occurrence and distribution of this species and, in particular, its multi-faceted impact on terrestrial and aquatic ecosystems and the main routes through which these impacts are being manifested. The bird-induced chemical loading and its biological and ecological consequences, and the effects on microbial pollution and pathogen dispersion are discussed in particular. The need for further investigation to fully elucidate particular effects is stressed throughout the paper. It is concluded that the environmental effects of great cormorants are rather complex, can lead to serious ecosystem modifications and that the presence of these birds should be taken into consideration in ecological assessment and monitoring.
PDF
