Food Habits of Juvenile American Alligators in the Upper Lake Pontchartrain Estuary

Food habits of juvenile (0.49-1.21 m total length) American alligators (Alligator mississippiensis) from an area in southeastern Louisiana were investigated. One-hundred and one stomach samples were obtained by stomach-pumping. Crustaceans (crayfish; blue crabs, Callinectes sapidus; grass shrimp, Palaemonetes sp.), insects (hemipterans, coleopterans), and small fish (least killifish, Heterandria formosa; mosquitofish, Gambusia affinis) constituted the majority of prey items taken. Fish consumption was significantly more frequent during April and May than during June through September (P\u3c0.025). This differential use of prey species may be due to seasonally fluctuating water levels in the study area. Comparisons of juvenile alligator food habits revealed dietary differences between Louisiana and Florida (P\u3c0.001), possibly due to the different prey available at the two areas. Prey utilization was not significantly different between larger alligators (0.9-1.2 m total length) and smaller alligators (0.3·0.9 m total length) (P\u3e0.25)

AN ADDITIONAL RECORD OF THE ORNATE BOX TURTLE FROM WESTERN SOUTH DAKOTA

On 11 June 2003, one of us (EJS) found an ornate box turtle crossing BIA Highway 2, approximately 7.2 km north of Sharps Comer on the Pine Ridge Indian Reservation in Shannon County, South Dakota. The air temperature at the time of collection was approximately 30°C, and the substrate was moist from light rain the previous day. The turtle was an adult female with a straight-line carapace length of 118 mm. Other straight-line measurements were: maximum carapace width = 100 mm; plastron length = 122 mm; maximum plastron width = 82 mm; and maximum shell depth = 64 mm. We deposited voucher photographs (CUSC 2166) of the turtle in the Campbell Museum, Clemson University, Clemson, South Carolina. Our specimen constitutes the first record of the ornate box turtle from Shannon County, and represents the westernmost occurrence of this species yet documented in South Dakota (Ballinger et al. 2000)

Predictors and immunological correlates of sublethal mercury exposure in vampire bats

Mercury (Hg) is a pervasive heavy metal that often enters the environment from anthropogenic sources such as gold mining and agriculture. Chronic exposure to Hg can impair immune function, reducing the ability of animals to resist or recover from infections. How Hg influences immunity and susceptibility remains unknown for bats, which appear immunologically distinct from other mammals and are reservoir hosts of many pathogens of importance to human and animal health. We here quantify total Hg (THg) in hair collected from common vampire bats (Desmodus rotundus), which feed on blood and are the main reservoir hosts of rabies virus in Latin America. We examine how diet, sampling site and year, and bat demography influence THg and test the consequences of this variation for eight immune measures. In two populations from Belize, THg concentrations in bats were best explained by an interaction between long-term diet inferred from stable isotopes and year. Bats that foraged more consistently on domestic animals exhibited higher THg. However, relationships between diet and THg were evident only in 2015 but not in 2014, which could reflect recent environmental perturbations associated with agriculture. THg concentrations were low relative to values previously observed in other bat species but still correlated with bat immunity. Bats with higher THg had more neutrophils, weaker bacterial killing ability and impaired innate immunity. These patterns suggest that temporal variation in Hg exposure may impair bat innate immunity and increase susceptibility to pathogens such as bacteria. Unexpected associations between low-level Hg exposure and immune function underscore the need to better understand the environmental sources of Hg exposure in bats and the consequences for bat immunity and susceptibility

Scavenging by a Bobcat, Lynx rufus

There are few available reports of scavenging (carrion foraging) by Bobcats (Lynx rufus). We recovered the remains of a Gray Squirrel (Sciurus carolinensis) from the stomach of a road-killed female Bobcat in Dutchess County, New York. The presence of Blow Fly eggs on the squirrel remains indicate that it was consumed as carrion. To our knowledge this is the third confirmed instance of scavenging by a Bobcat

Winterkill and Biomass of the Painted Turtle in a South Dakota Wetland

Winterkill occurs when drought conditions expose hibernating turtles to desiccation and lethaly cold temperatures. Winterkill is thought to represent a major source of mortality in northern populations of the painted turtle (Chrysemys picta), but few field observations are available. We herein reported on catastrophic winterkill among western painted turtle (C. pieta bellii) at Limestone Butte Lake (LBL) in western South Dakota during the winter of 2003-2004. Additionally, we used the carcasses of winterkilled turtles (n = 86) to estimate the standing crop biomass of the painted turtle at LBL (0.6 kg/ha). This was the only estimate of biomass available for a painted turtle population in South Dakota and one of only two for the Great Plains; furthermore, it was the lowest estimate from anywhere in North America. We attributed this to several factors, including the painted turtle probably began emigrating from LBL in response to receding water levels before the winterkill event of 2003-2004

Organochlorine Pesticides in Chlorioallantoic Membranes of Morelet\u27s Crocodile Eggs from Belize

Recent studies examined the utility of the chorioallantoic membrane (CAM) as a nonlethal, noninvasive indicator of environmental contaminant exposure in oviparous wildlife. The CAM is a highly vascularized extraembryonic membrane that functions as a site for respiration, nutrient transport, and waste storage during embryonic development. After hatching, the CAM is usually discarded with the eggshell and can be used for chemical residue analysis. Chorioallantoic membranes have been used successfully to examine contaminant exposure and predict chemical concentrations in multiple species of birds and reptiles. In this study, we examined organochlorine (OC) pesticide concentrations in CAMs from eggs of Morelet\u27s crocodiles (Crocodylus moreletii) from northern Belize. Multiple OCs were detected in crocodile CAMs, including aldrin, dieldrin, endrin, dichlorodiphenyltrichloroethane, dichlorodiphenyldichloroethane, dichlorodiphenyldichloroethylene (DDE), heptachlor, lindane, and methoxychlor. Number and concentrations of OC compounds in CAMs were variable. The most prevalent contaminant detected was DDE, which occurred in 69% of CAMs, with concentrations ranging from 0.3 parts per billion (ppb) to 17.0 ppb. The OC burdens in crocodile CAMs confirm contamination of eggs and suggest exposure in embryos and maternal females. These results further support the use of CAMs as qualitative indicators of OC exposure in oviparous wildlife. The efficacy of this sampling technique in the field will depend on the logistics and cost associated with CAM collection and the specific life history traits of the wildlife species

Low levels of nucleotide diversity in Crocodylus moreletii and evidence of hybridization with C. acutus

Examinations of both population genetic structure and the processes that lead to such structure in crocodilians have been initiated in several species in response to a call by the IUCN Crocodile Specialist Group. A recent study used microsatellite markers to characterize Morelet\u27s crocodile (Crocodylus moreletii) populations in north-central Belize and presented evidence for isolation by distance. To further investigate this hypothesis, we sequenced a portion of the mitochondrial control region for representative animals after including samples from additional locales in Belize, Guatemala and Mexico. While there is limited evidence of subdivision involving other locales, we found that most of the differentiation among populations of C. moreletii can be attributed to animals collected from a single locale in Belize, Banana Bank Lagoon. Furthermore, mitochondrial DNA sequence analysis showed that animals from this and certain other locales display a haplotype characteristic of the American crocodile, C. acutus, rather than C. moreletii. We interpret this as evidence of hybridization between the two species and comment on how these new data have influenced our interpretation of previous findings. We also find very low levels of nucleotide diversity in C. moreletii haplotypes and provide evidence for a low rate of substitution in the crocodilian mitochondrial control region. Finally, the conservation implications of these findings are discussed