HEALTH STATUS OF RED-FOOTED BOOBIES ( SULA SULA) DETERMINED BY HEMATOLOGY, BIOCHEMISTRY, BLOOD GASES, AND PHYSICAL EXAMINATION

HEALTH ASSESSMENT OF BLUE-FOOTED BOOBIES (SULA NEBOUXII EXCISA) DETERMINED BY HEMATOLOGY, BIOCHEMISTRY, BLOOD GASES, AND PHYSICAL EXAMINATION IN THE GALÁPAGOS ISLANDS

The Galápagos blue-footed booby (Sula nebouxii excisa) is a sulid species endemic to the Galápagos archipelago. Here we present physical examination, breeding status, hematology, and blood chemistry results from 60 Galápagos blue-footed boobies that were captured by hand from their nesting site on North Seymour Island in June 2017 and July 2022. A portable blood analyzer (iSTAT) was used to obtain values in the field for hematocrit, hemoglobin, sodium, potassium, chloride, ionized calcium, total CO2, glucose, blood urea nitrogen, creatinine, and anion gap for each bird. Blood lactate, total solids, packed cell volume, and blood smears were also assessed. A white blood cell differential was performed in 2017. The breeding status of each bird and the number of chicks in the nests were also recorded. Total CO2, blood urea nitrogen, ionized calcium, potassium, anion gap, hematocrit, and hemoglobin were all higher in 2022 than in 2017. There were also more nests with chicks in 2022 than in 2017. Lactate, ionized calcium, hematocrit, and hemoglobin were all higher in females than in males, and blood urea nitrogen was higher in males than in females. These results provide a reference to the baseline health parameters in a free-living population of Galápagos blue-footed boobies that can be used to monitor the health status of this species.

Implications of plastic ingestion on the growth and fledging success of shearwaters

Ingestion of plastic can have negative health consequences for wildlife. However, our understanding of the physiological impacts of plastics is limited, often relying on opportunistic sampling. We partnered with Tasmanian Aboriginal seabird harvesters, wildlife rescue clinics, and parks managers, to collect >400 fledgling yula/short-tailed and flesh-footed shearwaters across a spectrum of body conditions. We explored blood chemistry, trace elements, and broadscale growth metrics as a proxy for seabird health in relation to ingested plastic. We found beached yula fledglings were smaller (wing cord and body mass) than other groups. However, no significant relationships were detected between plastic ingestion and any health parameter. Critically evaluated, our findings are comparable to exposure data from similar fledgling seabird (petrel and shearwater) studies globally. These results suggest that plastic exposure across most same-size petrels and shearwater fledgling populations worldwide is probably below the threshold where sub-lethal health impacts can be expected, which we posit occurs when loads exceed 1-3 % of body mass. These findings indicate the need to quantify dose-risk responses for seabirds, and wildlife more generally.

Health status of the red-billed tropicbird (Phaethon aethereus) determined by hematology, biochemistry, blood gases, and physical examination

The red-billed tropicbird, Phaethon aethereus, is a species of seabird native to the Galápagos archipelago, and widely distributed across the neotropics. General health, blood chemistry, and haematology parameters have not been published for this species. Blood analyses were performed on samples drawn from 51 clinically healthy red-billed tropicbirds captured from their burrows at Islote Pitt on San Cristóbal Island in July, 2016 (21) and Daphne Major Island in June, 2017 (30). In the field, a point of care blood analyser (iSTAT) was used to obtain results for HCO3-, pH, pCO2, pO2, TCO2, iCa, Na, K, Cl, Hb, HCT, anion gap, creatinine, glucose and urea nitrogen. Additionally, a portable Lactate PlusTM analyser was used to measure blood lactate, and blood smears were also created in situ. The blood slides were used to estimate leukocyte counts and 100-cell differentials. Alongside these biochemistry and haematology parameters, average heart rate, respiratory rate, body temperature and scaled mass index (calculated from weight and a body measurement) were compared to determine the standard measurements for a healthy individual. The baseline data, and reference intervals reported in this paper are essential to detecting changes in the health of red-billed tropicbirds in the future.

INVESTIGATING BLOOD LACTATE CONCENTRATION AS A PROGNOSTIC INDICATOR FOR BIRDS PRESENTING WITH BREVETOXICOSIS: 2020-2021

Large blooms of the dinoflagellate Karenia brevis cause annual harmful algal bloom events, or "red tides" on Florida's Gulf Coast. Each year, the Clinic for the Rehabilitation of Wildlife (CROW) is presented with hundreds of cases of aquatic birds that exhibit neurologic clinical signs due to brevetoxicosis. Double-crested cormorants (Phalacrocorax auratus) are the most common species seen, and typically present with a combination of ataxia, head tremors, knuckling, and/or lagophthalmos. Blood lactate levels are known to increase in mammals for a variety of reasons, including stress, hypoxia, sepsis, and trauma, but there is limited literature on blood lactate values in avian species. The objective of this study was to determine the prognostic value of blood lactate concentration on successful rehabilitation and release of birds presenting with clinical signs consistent with brevetoxicosis. Blood lactate levels were collected on intake, the morning after presentation and initial therapy, and prior to disposition (release or euthanasia) from 194 birds (including 98 cormorants) representing 17 species during the 2020-2021 red tide season. Overall, mean blood lactate at intake, the morning after intake, and predisposition was 2.9, 2.8, and 3.2 mmol/L, respectively, for released birds across all species (2.9, 2.9, and 3.2 mmol/L for released cormorants); 3.4, 3.4, and 6.5 mmol/L for birds that died (4.0, 3.5, and 7.9 mmol/L for cormorants that died); and 3.1, 3.5, and 4.7 mmol/L for birds that were euthanized (3.5, 4.7, and 4.9 mmol/L for cormorants that were euthanized). On average, birds that died or were euthanized had an elevated lactate at all time points as compared to those that were released, but these results were not statistically significant (P = 0.13). These results indicate that blood lactate levels do not appear to be useful as a prognostic indicator for successful release of birds, including double-crested cormorants, affected by brevetoxicosis.

Revisiting glucose regulation in birds - A negative model of diabetes complications

Birds naturally have blood glucose concentrations that are nearly double levels measured for mammals of similar body size and studies have shown that birds are resistant to insulin-mediated glucose uptake into tissues. While a combination of high blood glucose and insulin resistance is associated with diabetes-related pathologies in mammals, birds do not develop such complications. Moreover, studies have shown that birds are resistant to oxidative stress and protein glycation and in fact, live longer than similar-sized mammals. This review seeks to explore how birds regulate blood glucose as well as various theories that might explain their apparent resistance to insulin-mediated glucose uptake and adaptations that enable them to thrive in a state of relative hyperglycemia.

HEALTH STATUS OF NAZCA BOOBIES (SULA GRANTI) ON DAPHNE MAJOR ISLAND IN THE GALÁPAGOS DETERMINED BY HEMATOLOGY, BIOCHEMISTRY, AND PHYSICAL EXAMINATION

Island species are particularly vulnerable to environmental disturbances and introduced pathogens. Conducting health assessments of wild populations in the Galápagos improves the ability of wildlife managers and veterinarians to detect deteriorations in health status. Seabirds in particular are useful species to monitor due to their colonial breeding and wide migration range. Nazca boobies (Sula granti) in a breeding colony at Daphne Major (n = 30) were given physical examinations, and blood samples were collected for hematology and biochemistry using an iSTAT Portable Clinical Analyzer. Female boobies had longer wing length than males, as well as lower blood urea nitrogen, creatinine, and white blood cell counts. This could be attributed to sexual dimorphism or differences in foraging and mating strategies between the sexes. The time between capture and blood collection had a significant inverse relationship on plasma sodium, potassium, hemoglobin, anion gaps, and lymphocyte counts, suggesting that blood sampling in Nazca boobies should be done in less than 5 m to avoid the impacts of stress on hematological parameters. This is the first health assessment on the breeding colony of Nazca boobies at Daphne Major, and the results can inform future monitoring in this species as well as other sulids.

Baseline haematology, biochemistry, blood gas values and health status of the Galapagos swallow-tailed gull (Creagrus furcatus)

The swallow-tailed gull, Creagrus furcatus, is a seabird endemic to the Galápagos archipelago. In general health, blood chemistry and haematology, parameters have not been published for this species. Blood analyses were run on samples drawn from 58 clinically healthy swallow-tailed gulls captured at Islote Pitt on San Cristóbal Island in July 2016 (28) and South Plaza Island in June 2017 (30). A point of care blood analyzer (iSTAT) was used in the field to obtain results for HCO₃ ^-, pH, pCO₂, pO₂, TCO₂, anion gap, chloride, creatinine, glucose, haematocrit, haemoglobin, ionized calcium, potassium, sodium and urea nitrogen. A portable Lactate Plus™ analyzer was used to measure lactate. The baseline data reported is valuable for comparisons amongst different populations in the archipelago and to detect changes in health status of Galápagos swallow-tailed gulls.

Venous Blood Analytes and Osmolality of Rehabilitated Juvenile Black-bellied Whistling Ducks (Dendrocygna autumnalis)

Venous blood samples were collected from 129 apparently healthy, rehabilitated juvenile black-bellied whistling ducks (Dendrocygna autumnalis) immediately before release from rehabilitation. Blood gas, electrolyte, and select biochemical and hematologic values were analyzed by using a point-of-care analyzer, and complete blood cell counts and osmolality were determined. Most biochemical analyte values were distributed parametrically, while most hematologic values were nonparametrically distributed. Calculated osmolality values were in poor agreement with measured osmolality values, and values of packed cell volume had poor agreement with hematocrit values determined with the i-STAT 1. The physiologic values reported provide vital information to assess individual duck health and guide fluid therapy in captivity and may prove useful to assess free-living population health of this duck species.