AVIFAUNISTIC DIVERSITY OF MERINE FOREST, NORTH-WEST ALGERIA

This study is an avifaunistic diversity assessment was carried out in the Merine forest, Sidi Bel Abbes (Northwest Algeria). During three years (2019-2021). The major objective of our investigation is to inventory avian species and to define their phenological categories. Among the important results is a record of, 71 species of bird, belonging to 17 orders and 28 families. The Passeriformes are the most noted with 43 species, distributed across 15 families, of which the Muscicapidae is the most represented with 10 species. The phenological categories indicates that the majority of this species are resident breeders (65 %), 21% are migrant breeders and 14% are passing visitors. Depending on trophic status, 32% are polyphagous, 27% insectivorous, 17% carnivorous, 15% granivorous and 8% omnivorous. In addition, we noted that, 31 species are protected by Flat 12-235 in Algeria, with one species (Falco naumanni) protected by the Ordinance 06-05. Internationally and one species protected according of the IUCN red list (Streptopelia turtur). The Merine forest is shelter to five species endemic to North Africa: Barbary Partridge (Alectoris barbara), Levaillant's Woodpecker (Picus vaillantii), Moussier's Redstart (Phoenicurus moussieri), Tristram's Warbler (Sylvia deserticola), African Blue Tit (Cyanistes teneriffae).

Male aggressiveness and risk-taking during reproduction are repeatable but not correlated in a wild bird population

The existence of among-individual variation in behaviour within populations is poorly understood. Recent theory suggests that fine-scale individual differences in investment into current versus future reproduction may lead to a ‘slow-fast’-pace-of-life continuum, also referred to as the ‘pace-of-life-syndrome’ (POLS) hypothesis. According to this idea, individuals are predicted to differ in their level of risk-taking, which may drive among-individual variation and covariation of behaviours. Consistent individual differences in aggression, an ecologically relevant and potentially risky behaviour, have been reported across the animal kingdom. Here we test whether such individual differences in aggression are a manifestation of underlying differences in risk-taking. In a wild blue tit (Cyanistes caeruleus) population, we used standard behavioural tests to investigate if male territorial aggressiveness and risk-taking during breeding are positively related. At the start of breeding, we simulated conspecific territorial intrusions to obtain repeated measures of male aggressiveness. Subsequently, we measured male risk-taking as their latency to resume brood provisioning after presenting two different predators at their nest: human and sparrowhawk, a common predator of adult songbirds. First, we found substantial repeatability for male aggressiveness (R = 0.56 ± 0.08 SE). Second, while males took longer to resume provisioning after presentation of a sparrowhawk mount as compared to a human observer, risk-taking was repeatable across these two predator contexts (R = 0.51 ± 0.13 SE). Finally, we found no evidence for a correlation between male aggressiveness and risk-taking, thereby providing little support to a main prediction of the POLS hypothesis. Significance statement Consistent, and often correlated, individual differences in basal behaviours, such as aggression, exploration and sociability, are found across the animal kingdom. Why individuals consistently differ in their behaviour is poorly understood, as behavioural traits would seem inherently flexible. The ‘pace-of-life syndrome’ (POLS) hypothesis proposes observed behavioural variation to reflect differences in risk-taking associated with individual reproductive strategies. We tested this idea in a wild blue tit population by investigating whether individual males that were more aggressive toward territorial intruders also took more risk when provisioning their nestlings under a threat of predation. While we found consistent individual differences in both aggressiveness and risk-taking, these behaviours were not significantly correlated. Therefore, our study demonstrates among-individual variation in ecologically relevant behaviours in wild blue tits but provides little support for the POLS hypothesis.

Social transmission in the wild can reduce predation pressure on novel prey signals

Social transmission of information is taxonomically widespread and could have profound effects on the ecological and evolutionary dynamics of animal communities. Demonstrating this in the wild, however, has been challenging. Here we show by field experiment that social transmission among predators can shape how selection acts on prey defences. Using artificial prey and a novel approach in statistical analyses of social networks, we find that blue tit (Cyanistes caeruleus) and great tit (Parus major) predators learn about prey defences by watching others. This shifts population preferences rapidly to match changes in prey profitability, and reduces predation pressure from naïve predators. Our results may help resolve how costly prey defences are maintained despite influxes of naïve juvenile predators, and suggest that accounting for social transmission is essential if we are to understand coevolutionary processes.

Faecal metabarcoding reveals pervasive long-distance impacts of garden bird feeding

Supplementary feeding of wildlife is widespread, being undertaken by more than half of households in many countries. However, the impact that these supplemental resources have is unclear, with impacts largely considered to be restricted to urban ecosystems. We reveal the pervasiveness of supplementary foodstuffs in the diet of a wild bird using metabarcoding of blue tit ( Cyanistes caeruleus ) faeces collected in early spring from a 220 km transect in Scotland with a large urbanization gradient. Supplementary foodstuffs were present in the majority of samples, with peanut ( Arachis hypogaea ) the single commonest (either natural or supplementary) dietary item. Consumption rates exhibited a distance decay from human habitation but remained high at several hundred metres from the nearest household and continued to our study limit of 1.4 km distant. Supplementary food consumption was associated with a near quadrupling of blue tit breeding density and a 5-day advancement of breeding phenology. We show that woodland bird species using supplementary food have increasing UK population trends, while species that do not, and/or are outcompeted by blue tits, are likely to be declining. We suggest that the impacts of supplementary feeding are larger and more spatially extensive than currently appreciated and could be disrupting population and ecosystem dynamics.