Effects of elevated nest box temperature on incubation behaviour and offspring fitness-related traits in the Collared Flycatcher Ficedula albicollis

Ambient temperature experienced by an animal during development or subsequently as an adult can affect many aspects of its behaviour and life-history traits. In birds, egg incubation is a vital component of reproduction and parental care. Several studies have suggested that environmental factors (such as nest microclimate) can influence the ability of incubating parents to maintain suitable conditions for embryo development. Here, we manipulated the developmental conditions of embryos through a modification of nest box thermal microclimate to investigate female incubation behaviour and its impact on offspring fitness-related traits in a wild population of the Collared Flycatcher (Ficedula albicollis). The temperature in experimental nests was increased using a heat-pack placed under the roof of a nest box, resulting in an average temperature increase of 2.5 ºC, which corresponds to projected climate change scenarios. We demonstrated that females from nests with elevated temperature spent less time in the nest box during egg incubation and had more off-bouts than females from control nests. Moreover, we found that offspring from the experimentally heated nests had larger body mass at fledging in comparison to the control ones. Our study indicates that nest microclimate during the incubation period affects female incubation behaviour and offspring quality, indicating that environmental variation in nest temperature early in ontogeny can have important and long-lasting fitness consequences.

Site-Specific Variation in Bacterial Loads of Wooden Nest Boxes in the Pre-Breeding Period

Among environmental factors affecting life - history traits of birds breeding in nest boxes, an influence of microbial communities is relatively poorly understood. In this study, nest boxes used for breeding by great tit (Parus major) and blue tit (Cyanistes caeruleus) were sampled before the start of the breeding season to assess the bacterial loads of the nest box. Samples from the entrance hole and the interior of the nest box were taken at two different study sites: an urban parkland and a natural forest. Nest boxes were sampled to check if their bacterial loads differed between habitats. The second objective of this study was to check whether the occupancy of the nest boxes during the previous season would influence the bacterial load of the nest box. To verify this prediction, two categories of nest boxes were sampled at both study sites: nest boxes occupied by any of the two tit species in the previous season for breeding and nest boxes that had remained empty that year. The bacterial load of the nest box was significantly higher in the forest study area in both the occupied and unoccupied nest boxes. The nest boxes used for breeding in the previous season had significantly higher bacterial loads, but only in the forest area. Our results suggest that the bacterial load of the nest box can vary between habitats and may be positively related to the presence of the nests in the previous breeding season.

Turn taking is not restricted by task specialisation but does not facilitate equality in offspring provisioning

Sexual conflict arises when two individuals invest in their common offspring because both individuals benefit when their partner invests more. Conditional cooperation is a theoretical concept that could resolve this conflict. Here, parents are thought to motivate each other to contribute to provisioning visits by following the rules of turn taking, which results in equal and efficient investment. However, parents have other tasks besides provisioning, which might hinder taking turns. To investigate restrictions by other care tasks and whether turn taking can be used to match investment, we manipulated brooding duration in female blue tits (Cyanistes caeruleus) during the early nestling phase by changing nest box temperature. As expected, females subjected to cold conditions brooded longer than females under warm conditions. Yet, contrary to our prediction, females had similar visit rates in both treatments, which suggests that females in the cold treatment invested more overall. In addition, the females’ turn taking level was higher in the more demanding cold condition (and the calculated randomised turn taking levels of females did not differ), hence females don’t seem to be restricted in their turn taking strategy by other care tasks. However, males did not seem to match the females’ turn taking levels because they did not adjust their visit rates. Thus, level of turn taking was not restricted by an other sex-specific task in females and did not facilitate a greater investment by their male partners.

Nest decoration: birds exploit a fear of feathers to guard their nest from usurpation

Many species of birds incorporate feathers into their nest as structural support and to insulate the eggs or offspring. Here, we investigated the novel idea that birds reduce the risk of nest usurpation by decorating it with feathers to trigger a fear response in their rivals. We let prospecting birds choose between a dyad of nest-boxes in the wild, both containing some nest materials, but where one had a few white feathers and the other had none. All three species of cavity-nesting birds studied, the pied flycatcher Ficedula hypoleuca , the blue tit Cyanistes caeruleus , and the tree swallow Tachycineta bicolor , hesitated to enter boxes with white feathers. A similar avoidance of white feathers was found when the alternative nest-box of a dyad held black feathers. However, the birds readily collected white feathers that we placed in front of their nest-box, showing the fear of such feathers was context-dependent. We suggest that naive prospecting birds may perceive feathers in nests as the result of a predation event, and that owners decorate nests with bright feathers that can be seen from the opening to deter others from entering.

PSV-9 The effect of management practices on eggshell cleanliness, bacteria levels and cuticle deposition in free-range poultry

Small-scale egg production is a growing industry in New England; however, foodborne illness risk exists from small-scale free-range eggs due to lack of guidelines for safe handling and management practices. We hypothesized that the manure level (ML) of the eggs along with management practices will affect both the total bacterial levels (relative light units= RLU) and the cuticle deposition (CD) of the eggshell. Hens (n = 53) were used in this study and housed at Peckham Farm (URI; Kingston, RI) in a mobile coop that allowed free ranging. The management practice experiments were divided into nest box type, location, substrate and time/frequency of collection. The CD experiments involved nesting boxes and nest substrate. Data were analyzed using SAS proc mixed/two sample t-test (P ≤ 0.05). There is a difference in ML between level 1 and 2 and level 1 and 3 eggs. Eggs collected from the conventional (CONV; n = 37) and rollaway (n = 25) nest boxes showed no difference in RLU or CD (P ≥ 0.42). Eggs collected from CONV with different nesting substrates (straw, shavings, AstroTurf nest pad; n = 179) showed no difference in RLU and CD (P ≥ 0.28). Nest box location (mounted vs floor level) showed no difference (P ≥ 0.65) in RLU values from eggs collected from CONV nest boxes. Time of collection (1pm vs 8 am) had a significant impact (P ≤ 0.02) in RLU values; however, frequency of collection showed no impact (P ≥ 0.49). The bacteria levels were most likely lower in the afternoon collection because the eggs laid that day did not spend as much time in nest boxes. In conclusion, although different nest boxes or substrates did not change eggshell bacteria levels, management practices that minimize manure levels on eggs and increase the frequency of collection can help to maintain lower bacteria levels to reduce food safety risk.

Urban-nesting mountain chickadees have a reduced response to a simulated predator

Anti-predator behaviour is common among birds, but little research exists on whether differences in the predator landscape between urban and rural habitats results in differential anti-predator behaviour. We compared nest-defence behaviour of mountain chickadees (Poecile gambeli) in urban and rural habitats in Kamloops, BC, Canada to a simulated predator model (snake) on top of nest boxes while incubating females were away from nests on foraging bouts. Upon their return, we recorded proximity to the predator model, latency to contact the nest box and enter the nest, and number of gargle and chick-a-dee calls as measures of anti-predator behaviour and compared multivariate “predator aversion scores” across birds occupying either rural or urban landscapes. Rural-nesting birds had more aversive reactions to the predator model than the urban-nesting birds, which may suggest differences in perceived threat of the model, in combination with increased boldness associated with urban-nesting birds.