Behaviour, hygiene, and lameness of dairy cows in a compost barn during cold seasons in a subtropical climate

This study aimed to assess the thermal environment, behaviour, hygiene, and lameness in dairy cows with different numbers of lactations housed in a compost-bedded pack barn system in a humid subtropical climate during autumn and winter. Between April and July 2016, behavioural and microclimatic environment assessments were conducted in a compost barn system, and hygiene and lameness assessments were performed. Crossbred cows in lactation (n = 10) were divided into two groups according to the number of lactations: primiparous and multiparous. Air temperature, relative humidity, and air ventilation speed were measured at 09:00, 12:00, and 15:00. The cows’ hygiene and lameness were evaluated using subjective scores ranging from 1 to 4 and 1 to 5, respectively. The daytime behaviour assessment was performed as sampling 0/1, using the focal method. Primiparous cows showed a greater probability of walking (P<0.05) than multiparous cows between 09:20 and 11:20, and at 15:20, and increased the water intake at 14:00. Regarding the eating behaviour and the effect of time of day within each group (P<0.05), the cows ate more in the morning’s early hours. The cows’ hygiene scores were 1 or 2, and most cows presented scores of 1 or 2 for lameness. Our research has shown that microclimatic variables may influence the walking behaviour and water intake of primiparous cows during the hottest periods of the day, even during cold weather, in a humid subtropical climate. The dairy cows showed low hygiene and lameness scores, which indicates that the compost bar positively influenced cleanliness and locomotion comfort.

Yellowfin Tuna Behavioural Ecology and Catchability in the South Atlantic: The Right Place at the Right Time (and Depth)

The yellowfin tuna (Thunnus albacares: YFT) is a widely distributed, migratory species that supports valuable commercial fisheries. Landings of YFT are seasonally and spatially variable, reflecting changes in their availability and accessibility to different fleets and metiers which, in turn, has implications for sustainable management. Understanding the dynamics of YFT behaviour and how it is affected by biological and ecological factors is therefore of consequence to fisheries management design. Archival and pop-up satellite tags (PSAT) were used in the South Atlantic Ocean around St Helena between 2015 and 2020 to collect information on the movements, foraging and locomotory behaviour of YFT. The study aimed to (1) identify vertical behaviour of YFT within St Helena’s EEZ; (2) assess the timing and depth of potential feeding events and (3) to use the information to inform on the catchability of YFT to the local pole and line fishing fleet. Results indicate that the YFT daytime behaviour shifted between shallow with high incidence of fast starts in surface waters in summer months (December to April), to deep with high incidence of strikes at depth in colder months (May to November). Catchability of YFT was significantly reduced between May and November as YFT spent more time at depths below 100 m during the day, which coincides with a reduction in the quantity of YFT caught by the inshore fleet.

Diurnal motor activity and “sunbathing” behaviour in crested porcupine (Hystrix cristata L., 1758)

The crested porcupine is a mainly nocturnal mammal that shows both moonlight avoidance and some diurnal motor activity, the latter as an extension of its night-time foraging behaviour. Furthermore, a peculiar daytime behaviour, described as “sunbathing”, was reported as episodic in H. africaeaustralis. Between 2016 and 2019 a camera-trapping monitoring was performed within 10 porcupine settlements in order to detect the diurnal motor activity and to verify and describe the sunbathing behaviour in crested porcupine. Out of 1,003 trap days, a total of 148 events of diurnal motor activity were recorded. The diurnal motor activity occurred throughout the year mainly between December and June from 15:00 to 16:00, with no statistical difference between cubs, youngsters and adults. The sunbathing behaviour was detected for a total of 36 episodes recorded. Sunbathing was performed mainly by cubs. The sunbathing behaviour occurred only between April and June during the hottest hours of the day (11:00 to 12:00). Diurnal motor activity and sunbathing behaviour of porcupine are discussed in relation to food availability and porcupine physiology.

Modelling the influence of daytime distribution on the transport of two sympatric krill species (Thysanoessa raschii and Meganyctiphanes norvegica) in the Gulf of St Lawrence, eastern Canada

Maps, F., Plourde, S., Lavoie, D., McQuinn, I., and Chassé, J. 2014. Modelling the influence of daytime distribution on the transport of two sympatric krill species (Thysanoessa raschii and Meganyctiphanes norvegica) in the Gulf of St Lawrence, eastern Canada. – ICES Journal of Marine Science, 71: 282–292. The Gulf of St Lawrence (GSL) provides several species of North Atlantic baleen whale with an abundant supply of krill, dominated by Thysanoessa raschii and Meganyctiphanes norvegica. We aimed to quantify the differences in upstream advection resulting from the interaction between the circulation and the specific diel vertical migration of T. raschii and M. norvegica at the scale of the northwest GSL. We coupled a regional circulation model with Lagrangian models where the daytime depth followed specific functions of surface salinity. Our results help to explain the spatio-temporal variability in both T. raschii and M. norvegica distributions. We identified in particular spatio-temporal patterns in krill upstream transport. During summer and autumn, the upstream transport of krill is steady across Jacques Cartier Strait, limited across Honguedo Strait, and more sporadic across the Estuary mouth. We estimated that the upstream advection of krill particles across the Estuary mouth would be higher by 16–17% for the T. raschii than for the M. norvegica daytime behaviour. Our results also suggest that the advective processes operating on the adults during the productive season are not the only cause for the observed magnitude of the interannual and interspecific variability in krill abundance.

Planktivore vertical migration and shoaling under a subarctic light regime

Visually foraging planktivorous fish are prey of visual predators, and their foraging behaviour may be affected by light levels both in terms of gain and risk. The large seasonal change in day length throughout a subarctic summer at 69°N was used to show the influence of light on diel vertical migration (DVM) and shoaling patterns in a planktivorous fish assemblage consisting of two species ( Coregonus lavaretus and Coregonus albula ). Under the midnight sun in June, night and daytime behaviour was similar, with extensive shoaling and limited DVM. With increasingly darker nights towards autumn, the fish dispersed during the dark hours and showed more extensive DVM. Throughout the changing light regime of both the day and the season, the planktivores consistently chose depths with light levels compatible with visual foraging and reduced predation risk as revealed from reactive distance modelling of coregonids and their salmonid predators. The findings support the hypothesis that behavioural decisions are based on a trade-off between foraging rate and predation risk, and increased predator avoidance behaviour towards autumn suggests that this trade-off is state-dependent.

Daytime micro-naps in a nocturnal migrant: an EEG analysis

Many species of typically diurnal songbirds experience sleep loss during the migratory seasons owing to their nocturnal migrations. However, despite substantial loss of sleep, nocturnally migrating songbirds continue to function normally with no observable effect on their behaviour. It is unclear if and how avian migrants compensate for sleep loss. Recent behavioural evidence suggests that some species may compensate for lost night-time sleep with short, uni- and bilateral ‘micro-naps’ during the day. We provide electrophysiological evidence that short episodes of sleep-like daytime behaviour (approx. 12 s) are accompanied by sleep-like changes in brain activity in an avian migrant. Furthermore, we present evidence that part of this physiological brain response manifests itself as unihemispheric sleep, a state during which one brain hemisphere is asleep while the other hemisphere remains essentially awake. Episodes of daytime sleep may represent a potent adaptation to the challenges of avian migration and offer a plausible explanation for the resilience to sleep loss in nocturnal migrants.

Daytime behaviour of the grey-headed flying fox Pteropus poliocephalus Temminck (Pteropodidae: Megachiroptera) at an autumn/winter roost.

The grey-headed flying fox (Pteropus poliocephalus Temminck) is a threatened large fruit bat endemic to Australia. It roosts in large colonies in rainforest patches, mangroves, open forest, riparian woodland and, as native habitat is reduced, increasingly in vegetation within urban environments. The general biology, ecology and behaviour of this bat remain largely unknown, which makes it difficult to effectively monitor, protect and manage this species. The current study provides baseline information on the daytime behaviour of P. poliocephalus in an autumn/winter roost in urban Sydney, Australia, between April and August 2003. The most common daytime behaviours expressed by the flying foxes were sleeping (most common), grooming, mating/courtship, and wing spreading (least common). Behaviours differed significantly between times of day and seasons (autumn and winter). Active behaviours (i.e., grooming, mating/courtship, wing spreading) occurred mainly in the morning, while sleeping predominated in the afternoon. Mating/courtship and wing spreading were significantly higher in April (reproductive period) than in winter (non-reproductive period). Grooming was the only behaviour that showed no significant variation between sample periods. These results provide important baseline data for future comparative studies on the behaviours of flying foxes from urban and ?natural? camps, and the development of management strategies for this species.