Epigenetic Potential in Native and Introduced Populations of House Sparrows (Passer domesticus)

Synopsis Epigenetic potential, defined as the capacity for epigenetically-mediated phenotypic plasticity, may play an important role during range expansions. During range expansions, populations may encounter relatively novel challenges while experiencing lower genetic diversity. Phenotypic plasticity via epigenetic potential might be selectively advantageous at the time of initial introduction or during spread into new areas, enabling introduced organisms to cope rapidly with novel challenges. Here, we asked whether one form of epigenetic potential (i.e., the abundance of CpG sites) in three microbial surveillance genes: Toll-like receptors (TLRs) 1B (TLR1B), 2A (TLR2A), and 4 (TLR4) varied between native and introduced house sparrows (Passer domesticus). Using an opportunistic approach based on samples collected from sparrow populations around the world, we found that introduced birds had more CpG sites in TLR2A and TLR4, but not TLR1B, than native ones. Introduced birds also lost more CpG sites in TLR1B, gained more CpG sites in TLR2A, and lost fewer CpG sites in TLR4 compared to native birds. These results were not driven by differences in genetic diversity or population genetic structure, and many CpG sites fell within predicted transcription factor binding sites (TFBS), with losses and gains of CpG sites altering predicted TFBS. Although we lacked statistical power to conduct the most rigorous possible analyses, these results suggest that epigenetic potential may play a role in house sparrow range expansions, but additional work will be critical to elucidating how epigenetic potential affects gene expression and hence phenotypic plasticity at the individual, population, and species levels.

Using citizen science to study exotic and invasive birds.

This chapter describes the current usage of citizen science to increase the current knowledge of exotic and invasive bird populations. Citizen science projects aimed at studying and tracking exotic birds are divided into two categories: those that are part of a broad-scale biodiversity collection scheme, and those that are species focused. Some of the current literature that integrates citizen science data and the effects, management and implications of introduced birds are summarized, and select examples that highlight the potential of citizen science aimed at gathering various types of information about exotic birds are included. A vision for the future of citizen science aimed at studying exotic birds is also discussed.

Diet of the Australian Hobby Falco longipennis breeding in Canberra, Australian Capital Territory, in 2002–2004 and 2005–2008

The diet of the Australian Hobby Falco longipennis was studied in Canberra (ACT), in the summers of 2002–2003 to 2004–2005 and 2005–2006 to 2008–2009 by analysis of prey remains and pellets (28 and 40 collections for a total of 229 and 132 prey items from six and four nests, respectively). The Hobbies’ breeding diet in the first period consisted of 73% birds, 1% microbats and 26% insects by number, and 98% birds, <1% microbats and 1% insects by biomass, mainly parrots (Psittaculidae), Common Starlings Sturnus vulgaris and sparrows Passer sp. In the second period, it consisted of 94% birds, 3% mammals (mostly microbats), 2% lizards and <1% insects by number, and was more dominated by Starlings and other introduced birds, with the change perhaps reflecting a recent decline in local insect abundance. The Hobby’s dietary metrics correspondingly shifted to a greater Geometric Mean Prey Weight and narrower food niche. The Hobby’s diet overlapped moderately (42%) with that of the similarly sized Collared Sparrowhawk Accipiter cirrocephalus in the ACT over the same timeframe, although the two are separated by foraging habitats and methods.

The impact of the Endangered Mauritian flying fox Pteropus niger on commercial fruit farms and the efficacy of mitigation

The endemic Mauritian flying fox Pteropus niger is perceived to be a major fruit pest. Lobbying of the Government of Mauritius by fruit growers to control the flying fox population resulted in national culls in 2015 and 2016, with a further cull scheduled for 2018. A loss of c. 38,318 individuals has been reported and the species is now categorized as Endangered on the IUCN Red List. However, until now there were no robust data available on damage to orchards caused by bats. During October 2015–February 2016 we monitored four major lychee Litchi chinensis and one mango (Mangifera spp.) orchard, and also assessed 10 individual longan Dimocarpus longan trees. Bats and introduced birds caused major damage to fruit, with 7–76% fruit loss (including natural fall and losses from fungal damage) per tree. Bats caused more damage to taller lychee trees (> 6 m high) than to smaller ones, whereas bird damage was independent of tree height. Bats damaged more fruit than birds in tall lychee trees, although this trend was reversed in small trees. Use of nets on fruiting trees can result in as much as a 23-fold reduction in the damage caused by bats if nets are applied correctly. There is still a need to monitor orchards over several seasons and to test non-lethal bat deterrence methods more widely.

Becoming Endemic

This chapter examines the Japanese White-eye, Zosterops japonicus, and the confounding nature of introduced species, some of which have been here long enough to have evolved into something unique to the islands. The White-eye, also known by its Japanese name Mejiro, has been a fixture in the islands since it was introduced on Oʻahu by the Hawaiʻi Board of Commissioners of Agriculture and Forestry (BCAF) in 1929, which was interested in birds primarily as a form of insect control. The White-eye's introduction was then continued by the Hui Manu, a private group founded in 1930 as an acclimatization society that introduced birds from around the world for aesthetic reasons.

Causes of bird losses recorded in a captive-bred wild bird flock between 2011 and 2015

ABSTRACT: This study discusses the causes of bird deaths recorded in a small aviary dedicated to the breeding of a few exotic, wild bird species. Findings from 28 birds were examined over a period of five years. About 40% of the deaths occurred in the first two weeks after hatching in the two most numerous species in the flock and such losses were mainly a result of starvation caused by inadequate nutritional management. Additionally, 28% of the cases affected recently introduced birds. Despite frequent treatment with anthelmintics; a total of 21% of the deaths in the flock could be attributed to parasitic diseases, most of them in recently acquired birds. Only three of the deaths could be associated with advanced age, all of the further cases were also attributable to management fails. Our results indicated that propagation of these and other species requires an improvement of the management of the newly hatched and newcomer birds to considerably enhance the flock’s performance. Such information may be useful in conservation initiatives and may justify, at least in part, captivity of these animals.