Recent data suggest that facultative hypothermic responses such as torpor are more important in the energy balance of birds from tropical and sub‐tropical regions than previously thought. We used telemetric measurements of skin temperature (Tskin) for five individuals on 151 bird‐nights to investigate the occurrence of torpor during winter in an 81 g African caprimulgid, the freckled nightjar Caprimulgus tristigma. We found that freckled nightjars have the capacity to enter torpor, with a minimum observed Tskin of 12.8°C. During the torpor bouts we observed, complete rewarming typically occurred after sunrise, and coincided with the availability of solar radiation. There was considerable inter‐individual variability in the frequency and depth of torpor bouts, with one female nightjar exhibiting particularly frequent and deep torpor. Our results confirm the ability to use torpor by a nocturnal aerial insectivore from the Afrotropics, and reiterate the variability in patterns of torpor that can exist within a population.

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We examined environmental correlates of activity in the Freckled Nightjar (Caprimulgus tristigma), a nocturnal aerial insectivore that is resident year-round in the colder and drier parts of southern Africa. Specifically, we tested the prediction that air temperature (T a ), in addition to light availability, is a significant correlate of Freckled Nightjar activity. We found that aerial insect density varied by over three orders of magnitude (from <1.0 to 117.1 insects 1,000 m −3) during the course of the study, and was strongly and positively related to T a . Nightjar activity was also significantly temperature-dependent, with a cessation of activity at T a < 12°C. Consistent with previous studies, we found that activity levels were strongly related to ambient light, with markedly reduced activity levels on dark nights. The average number of Freckled Nightjars encountered per 14.6-km transect was 1.95 ± 2.44 nightjars transect around new moon. Our study reveals that caprimulgid activity can be significantly influenced by temperature as well as ambient light.

Coat colour patterns are important characteristics of many cattle breeds and in some are determined by a chromosomal translocation, which can have the pleiotropic effect of testicular hypoplasia. We test the hypothesis that this variant, known as the Cs 29 allele, is prevalent in the ancient Chillingham White Cattle (Bos taurus) of north-east England. Its distribution may provide insights into breed history, and as it is associated with reproductive anomalies, we investigated the issues of subfertility in this cattle herd which are of clear relevance to its conservation. We report that the cattle are homozygous for the translocation. As it is also known in other breeds of the England-Scotland border and northern Irish area, namely the White Galloway and Irish Moiled, and in the Northern Finncattle and Swedish Mountain, we further hypothesize a Scandinavian connection for White Galloway, Irish Moiled and Chillingham cattle. We present unpublished data showing testicular hypoplasia to be present at Chillingham. Sperm quality is also known to be very low, and the question arises as to how the highly inbred (F is = 0.92) Chillingham cattle have continued to survive in spite of these reproductive anomalies. Surprisingly, herd fertility has not declined over the last 160 years, and in the light of behavioural data, we propose this is probably because of multiple mating, there being no castration and only welfare culling in this herd. These findings have wide relevance, particularly for breeds of conservation importance and probably for other bovine species, because male subfertility, frequent in cattle generally, could restrict the choice of bulls for representation in gene banks with consequent risk of loss of lineages. Research on heterospermic insemination or multiple mating of cattle could, therefore, be a useful complement to the development of assisted reproduction technologies for cryoconservation.

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