Maggie J. Watson

What drives population-level effects of parasites? Meta-analysis meets life-history

Graphical abstract

Differences in Foraging Performance between Juvenile and Adult Roseate Terns at a Pre-Migratory Staging Area

-Complex foraging skills may be acquired slowly and may therefore improve with age and experience. This note compares foraging proficiency of adult Roseate Terns (Sterna dougallii) to that ofjuveniles aged eight to ten weeks (still being fed by parents) at a pre-migratory staging area located on Nantucket Island, MA, USA. Adults used high plunge dives exclusively, while juveniles used four different dive types. Adults were statistically superior foragers. Juveniles had a lower capture rate (0.27 prey captures/min) and were less successful (0.15 prey captures/ attempt) than adults (0.98 prey captures/min; 0.52 prey captures/attempt). These data are discussed in light of extended parental care in Roseate Terns. Received 29 August 1999, accepted 8 September 1999.

On the benefits of systematic reviews for wildlife parasitology.

Systematic reviews and meta-analyses are widely accepted as the best means to synthesise quantitative or qualitative scientific evidence. Many scientific fields have embraced these more rigorous review techniques as a means to bring together large and complex bodies of literature and their data. Unfortunately, due to perceived difficulties and unfamiliarity with processes, other fields are not using these options to review their literature. One way to provide guidance for a specific field is to examine critically recent reviews and meta-analyses and to explain the advantages and disadvantages of the various review techniques. In this paper, we examine review papers in the emerging field of wildlife parasitology and compare five different literature review types—configurative narrative review, aggregative scoping review, aggregative literature review, aggregative meta-analysis, and aggregative systematic review. We found that most literature reviews did not adequately explain the methodology used to find the literature under review. We also found that most literature reviews were not comprehensive nor did they critically appraise the literature under review. Such a lack severely reduces the reliability of the reviews. We encourage all authors to consider using systematic reviews in the future, and for authors and peer-reviewers to be aware of the limitations of non-systematic reviews.

Post-fledging brood and care division in the roseate tern (Sterna dougallii)

Extended post-fledging parental care is an important aspect of parental care in birds, although little studied due to logistic difficulties. Commonly, the brood is split physically (brood division) and/or preferential care is given to a subset of the brood by one parent or the other (care division). Among gulls and tern (Laridae), males and females generally share parental activities during the pre-fledging period, but the allocation of parental care after fledging is little documented. This study examined the behaviour of male and female roseate terns (Sterna dougallii) during the late chick-rearing and early post-fledging periods, and in particular the amount of feeds and the time spent in attendance given to individual chicks/fledglings. Pre-fledging parental care was biparental in all cases. Post-fledging parental care was dependent on the number of fledglings in the brood. Males and females continued biparental care in clutches with one surviving fledgling, while in two-fledgling clutches, males fed the A-fledgling while females fed the B-fledgling. Overall, there was no difference in attendance, only in feeds. This division of care may be influenced by the male only being certain of the paternity of the A-chick but not by chick sex.

Effects of acid pigeon excreta on building conservation

Purpose n n n n nBirds are implicated in spoiling and decay of buildings, especially through their droppings. Pigeons are considered the main culprits, and several studies have examined the effects and chemistry of accumulations of droppings without evidence to the exact origins of the source of the excreta. The paper aims to discuss these issues. n n n n nDesign/methodology/approach n n n n nThis study reviews and summarises the state of knowledge with regard to the impact of bird excreta on buildings. It experimentally assesses the acidity of fresh pigeon excreta with different diets and examines the development of the acidity of the excreta after voiding. n n n n nFindings n n n n nFeral pigeons in urban settings are known to be fed by a range of foods. Urban food scraps-derived diets produce more acidic excreta than more natural diets such as seeds. This is a first study of its kind to examine the impact of a bird’s diet on the pH and thus the resulting (potential) decay of masonry. n n n n nResearch limitations/implications n n n n nThis study showed that from a management’s perspective, pigeons that subsist entirely on human provided foods will be depositing more initially acidic faeces. If faecal accumulation occurs; then, mould and other bacteria quickly alter the chemistry from acidic towards basic, but the damage may already be done. n n n n nOriginality/value n n n n nThis paper is the first study of its kind to examine the effects of fresh pigeon droppings of known origin and age once voided from the intestine. This allows the authors to assess the impact during the first few days.

Building use by urban commensal avifauna in Melbourne central business district, Australia

ABSTRACT The foraging and perching behaviours of urban commensal birds are well studied but disproportionately focused on green spaces (e.g. parks, backyards) rather than inner city urban sites. The relationship between building use and foraging was examined in free-ranging urban birds of the central business district (CBD) of Melbourne, Victoria, Australia during 2015–2016. The presence of common birds on urban buildings was attributable both to the time of day (Feral Pigeons and Silver Gulls in the morning, and House Sparrows in the evening) and the architectural period of the building (Feral Pigeons, House Sparrows and Common Mynas were found mostly on historic buildings). The proximity of buildings to tree cover had a significant impact on the presence of House Sparrows. Silver Gulls were present in large numbers only in areas with the least disturbance from traffic and trams (and their overhead wires). Feeding behaviours constituted a small portion of time budgets for all species (mean 4.3%; range 0–11%) compared to perching (28.2; 0–60%), walking (30.4; 0–80%) and flying (23.0; 0–54%), indicating that food sources were highly abundant and requiring little effort to acquire. Management implications of this study support control of food availability rather than costly and ineffective bird deterrent systems on buildings.

Behaviour of Pigeon Excreta on Masonry Surfaces

Abstract Pigeon droppings are implicated in spoiling and decay of buildings. Several studies have examined the effects and chemistry of accumulations of pigeon droppings under highly localised pigeon roosts. Scant information exists on the impact caused by individual pigeon droppings at perch sites, even though these constitute the majority of bird use in urban areas. This study experimentally examined the processes that affect masonry immediately after pigeon excreta have been voided from the body and what effects discrete, fresh pigeon droppings have on different kinds of sandstone. The experiments demonstrated the susceptibility of freshly deposited excreta to environmental conditions (relative humidity and precipitation). In real-life situations, with pigeon excreta deposited on window ledges, cornices and parapets, the majority of damage would occur within the first two weeks of deposition. After that, the majority of individual droppings would have either dissolved or desiccated to such a degree that they would have rolled off. Much of the observed staining is superficial. While individual bird droppings make a building look dirty, even for months at a time, the effect on the building material is not substantial unless other factors come into play such as colonisation of the excreta by mould or leaching of salts from the excreta.

Bird impacts on heritage buildings: Australian practitioners’ perspectives and experiences

There is much anecdotal evidence that birds and their droppings are a major problem for the heritage profession. The purpose of this paper is to examine how serious heritage practitioners consider the bird impact to be.,An online survey was conducted of 59 Australian heritage professionals of between one and >20 year’s experience in the field.,Bird impacts were not considered of major concern to buildings. The longer experience a practitioner had, the less likely the impacts were considered an issue. Feral pigeons were deemed the most problematic, followed by cockatoos, starlings, swallows, seagulls, mynas, sparrows, cormorants, ibis, ducks and birds of prey. The professionals ranked common deterrent methods. The highest-ranking deterrents were bird netting and bird spikes, but they were only considered moderately effective. The costs of installation and maintenance, as well the ease of installation, were all deemed significantly less important than the physical impact, the aesthetic sympathy and the effectiveness of a deterrent method.,This study indicates that the impact of birds on buildings in Australia may be of less concern than previously thought, and may be driven by other factors (i.e. aesthetics, commercial companies) rather than actual effects.,This is first study of its kind that surveyed the experiences of a wide range of heritage practitioners.

Dietary habits of urban pigeons (Columba livia) and implications of excreta pH – a review

Abstract Pigeons are considered to be urban pests, causing untold damage to buildings and potentially impacting the health of humans who come into contact with them or their faeces. Pigeon faecal matter has been implicated in both health impacts and building damage, with the acidity of the excreta playing an important role. Purpose of the Review. This paper is a wide-ranging review of the chemical processes of excreta in the pigeon to aid our understanding of the potential problems of pigeons to buildings and human amenity in the urban space. The natural pH of pigeons is shown to vary based on the bird’s and age as well as reproductive stage. Key findings of the review. The influences of the altered diet between the rock dove (the wild progenitor of the feral pigeon) and the feral pigeon are detailed, indicating that the human-based diet of urban pigeons most likely causes the feral pigeon excreta to be more acidic than the rock dove excreta. This higher acidity is due in part to diet, but also to potential increases in faecal and/or uric acid volumes due to the low quality of human-based diets. Again, this area of interest is highly data deficient due to the few number of studies and unspecified dietary intake before pH measurement. Implications of the review. Humans are increasingly concerned about pigeon populations (and presumably their accumulated faeces) in the urban space, and control comprises a large part of the interaction between humans and feral pigeons. This review provides a greater understanding of feral pigeons and the true effects of their excreta.