Satellite Tracking Reveals Nesting Patterns, Site Fidelity, and Potential Impacts of Warming on Major Green Turtle Rookeries in the Red Sea

Major aggregations of nesting green turtles (Chelonia mydas) occur in the northern Red Sea, although little is known about the reproductive ecology of this endangered species in the region. To address this issue, we satellite-tracked 30 female green turtles to document their movements and to identify factors driving habitat use at two major rookeries in the Red Sea, Jazirat Mashabah (Mashabah Island) and Ras Al Baridi in Saudi Arabia. Between successive nesting events, turtles displayed high fidelity to nesting beaches and adjacent in-water habitats (inter-nesting habitats). Using generalized linear mixed models, we estimated the mean probability of nesting per beach emergence (nesting success rate) to be 0.628, and the mean duration between a successful nesting event and the successive emergence onto the beach (re-nesting interval) to be 10.8 days at each site. The nesting success rate was relatively high (>0.8) when the preceding daytime land surface temperature (LST) was lower than 37°C but decreased with elevated daytime LST (<0.4 when >47°C). Re-nesting interval was longer at lower water temperatures and towards the end of the nesting season of individuals. Our study improves the robustness of abundance estimates from census data (e.g., track counts) and shows that the protection of nesting and inter-nesting habitats during a breeding season would be an effective conservation strategy for the species. We discuss how global warming could increase energy expenditure due to lowered nesting success, ultimately compromising the reproductive fitness of these populations.

Comparative nesting patterns and success of Mynas and Starlings (Aves: Sturnidae) inhabiting Jahangirnagar University campus, Bangladesh

Nesting patterns of four species of mynas and starlings, Common Myna (Acridotheres tristis), Jungle Myna (Acridotheres fuscus), the Asian-pied Starling (Gracupica contra) and Chestnut-tailed Mtarling (Sturnia malabarica) were studied in Jahangirnagar University campus from March to September in 2016. Nests were searched systematically throughout the study area and nesting parameters like nest dimensions, nest-site selection, tree species preference, nesting materials, clutch size and nesting success were examined. A total of 101 nests were recorded where 31 nests were of Common Myna, 10 of Jungle Myna, 49 of the Asian-pied Starling and 11 nests were of Chestnut-tailed Starling. Overall, the sturnids preferred nesting on trees (n=84) to anthropogenic structures (n=17). Common myna showed maximum variation in nest-site selection using tree holes (n=12), tree branches (n=10) and building cornices, holes or crevices (n=9) whereas Chestnut-tailed Starling nested only in tree cavities (n=11). Jungle Myna built nests both in tree holes (n=4) and in building holes and crevices (n=6). The Asian-pied Starlings built their domed nests mostly on tree branches (n=47) where 69% nests were peripheral and 31% were central in position. Out of 20 species of trees utilized for nesting purpose, the majority of nests were built on Whites iris Albizia procera (n=18) followed by Neem Azadirachta indica (n=10) and Mahogany Swietenia mahagoni (n=10). The nests were constructed between 2 and 18m (8±3.8m) from the ground level. Among 19 types of nesting materials recorded, twigs, leaves, straws, grasses, feathers, plastics and polythene were frequently used by all four species while the Asian-pied starling used more rubbish materials than other species. Highest nesting success (80%) was recorded in Common Myna whereas the Asian-pied Starling, Chestnut-tailed Starling and Jungle Myna had 77.8%, 75% and 66.7% of nesting success respectively. Adaptions to using different nesting sites in Common Myna and comparatively higher nesting height in the Asian-pied Starling may have facilitated the greater nesting success. Bangladesh J. Zool. 48(2): 321-334, 2020

Presence of Pathogen-killed Larvae Influences Nesting Behavior of the Alfalfa Leafcutting Bee (Hymenoptera: Megachilidae)

The alfalfa leafcutting bee (Megachile rotundata (Fabricius)), a commercial pollinator used for alfalfa seed production, is susceptible to chalkbrood disease via ingested fungal spores. Diseases of insects can elicit behavioral changes in their hosts, but there are no recorded behaviors of alfalfa leafcutting bees in response to this fungal exposure. We conducted field studies to determine whether bees in pathogen-dense environments altered their nesting patterns, specifically if bees exposed to fungal spores produced higher numbers of nest cells and whether the proportions of nest cells that failed as eggs or small larvae (a state known as ‘pollen ball’) were greater. We found that our control bees, nontreated bees which were not exposed to chalkbrood spores other than those in the natural environment, had the highest proportion of pollen ball cells. Bees experimentally exposed to infective spores created the lowest number of nests and the fewest cells. Bees experimentally exposed to heat killed noninfective spores produced the greatest number of nests and cells overall and the greatest number of healthy progeny. We conclude that there are underlying behaviors that are elicited in response to the presence of chalkbrood spores that reduce the proportion of failed nest cells (grooming) and increase retention of bees at nesting sites (delay of bee emergence). Through further study of these behaviors, bee managers can potentially increase the productivity of their bee populations.

Urban Hedgehog Behavioural Responses to Temporary Habitat Disturbance versus Permanent Fragmentation

Anthropogenic activities can result in both transient and permanent changes in the environment. We studied spatial and temporal behavioural responses of European hedgehogs (Erinaceus europaeus) to a transient (open-air music festival) and a permanent (highly fragmented area) disturbance in the city of Berlin, Germany. Activity, foraging and movement patterns were observed in two distinct areas in 2016 and 2017 using a “Before & After“ and “Control & Impact“ study design. Confronted with a music festival, hedgehogs substantially changed their movement behaviour and nesting patterns and decreased the rhythmic synchronization (DFC) of their activity patterns with the environment. These findings suggest that a music festival is a substantial stressor influencing the trade-off between foraging and risk avoidance. Hedgehogs in a highly fragmented area used larger home ranges and moved faster than in low-fragmented and low-disturbed areas. They also showed behaviours and high DFCs similar to individuals in low-fragmented, low disturbed environment, suggesting that fragmentation posed a moderate challenge which they could accommodate. The acute but transient disturbance of a music festival, therefore, had more substantial and severe behavioural effects than the permanent disturbance through fragmentation. Our results are relevant for the welfare and conservation measure of urban wildlife and highlight the importance of allowing wildlife to avoid urban music festivals by facilitating avoidance behaviours.

Nesting Patterns of Loggerhead Sea Turtles (Caretta caretta): Development of a Multiple Regression Model Tested in North Carolina, USA

Numerous environmental conditions may influence when a female Loggerhead sea turtle (Caretta caretta) selects a nesting site. Limited research has used Geographic Information Systems (GIS) and statistical analysis to study sea turtle spatial patterns and temporal trends. Therefore, the goals of this research were to identify areas that were most prevalent for nesting and to test social and environmental variables to create a nesting suitability predictive model. Data were analyzed at all barrier island beaches in North Carolina, USA (515 km) and several variables were statistically significant: distance to hardened structures, beach nourishment, house density, distance to inlets, and beach elevation, slope, and width. Interestingly, variables that were not significant were population density, proximity to the Gulf Stream, and beach aspect. Several statistical techniques were tested and Negative Binomial Distribution produced good regional results while Geographically Weighted Regression models successfully predicted the number of nests with an average of 75% of the variance explained. Therefore, the combination of traditional and spatial statistics provided insightful predictive modeling results that may be incorporated into management strategies and may have important implications for the designation of critical Loggerhead nesting habitats.