Nancy M. Harrison

Mixed-species flocks: an example of niche construction?

Mixed-species flocks result from coevolved relationships between participants: interspecific gregariousness that varies in strength in different species pairs or groups. Such interspecific associations of birds are a characteristic of most avian communities, observed in diverse habitats from forests to grasslands and from estuaries to the open ocean, both at high latitudes and in the tropics. We explore the consequences of mixed-species flocks in shaping the selection environment and discuss whether the participants in flocks should be identified as niche constructors. As a result of the decision to associate with other species, a bird alters its relationship with competitors, potentially gains access to resources, becomes safer from predators and may change microhabitat use. The recurrent patterns in the behaviour of disparate unrelated species active in mixed-species flocks have led investigators to conclude that similar selection pressures have shaped their behaviour. However mixed-species flocks are variable in their characteristics, the birds active in them are diverse in form and behaviour, and the selection pressures that have shaped their propensity to join mixed-species flocks must be various. In forming mixed-species flocks, species with specialized roles at the centre of flocks are creating a complex social environment that represents an important biotic selection force shaping their own ecology and behaviour, and that of other species within the avian community. In this review, we consider how the spectrum of interspecific relationships in mixed-species flocks makes them an interesting focus for further studies of niche construction by relocation.

Merging Wildlife and Environmental Monitoring Approaches with Forensic Principles: Application of Unconventional and Non-Invasive Sampling in Eco- Pharmacovigilance

Pharmaceutical residues in the environment have the potential to harm wildlife. A population’s fragility or an animal’s secretive nature may preclude capture and the use of invasive/destructive sampling techniques that are typically used in a risk assessment. Conventionally favoured matrices gathered opportunistically from carcasses have a finite lifespan, thereby limiting the detection window. This multidisciplinary paper aims to promote the use of non-invasive approaches and optimize use of even the most degraded carcasses. We highlight a selection of promising alternative, unconventional and underutilized sample types that could be applied in environmental monitoring efforts and wildlife forensic investigations. With a focus on non-steroidal anti-inflammatory drugs (NSAIDs), now under increasing scrutiny in the freshwater and terrestrial environment, we first illustrate current sampling practices and gaps in knowledge by summarizing exposure of: 1) aquatic organisms to urban effluent discharged into waterways, and, 2) scavenging species to veterinary residues in livestock and other carrion. We then consider the merits and limitations of a range of alternative environmentally robust sample options that offer a broader detection interval for NSAIDs, with emphasis on hair, wool and feathers. The viability of eyes/ocular material, bone matter, fecal matter, injection sites, ingesta/pellets and scavenging/coprophagous insects are also discussed.

Preferred Habitat of Breeding Birds May Be Compromised by Climate Change: Unexpected Effects of an Exceptionally Cold, Wet Spring

Previous studies of the consequences for breeding birds of climate change have explored how their populations may respond to increasing temperatures. However, few have considered the likely outcome of predicted extreme conditions and the relative vulnerability of populations in different habitats. Here, we compare phenology and breeding success in great tits and blue tits over a 10 year period, including the extremely harsh conditions during spring 2012, at three sites in eastern England – mixed deciduous woodland, riparian and urban habitat. Production, measured as brood biomass, was significantly lower in 2012 compared with the previous 9 years, with the decrease in productivity relatively greatest in woodland habitat. Production was related to hatch delay, i.e. birds not initiating incubation immediately after clutch completion, which was more common in 2012 than in previous years. The best predictor of hatch delay was daytime temperature (not nighttime minimum temperature) and rainfall, which convincingly reflected low growth and activity of caterpillar prey. We found that birds breeding in riparian and urban habitats were less vulnerable to the extremes of weather than those breeding in mixed deciduous woodland.

Qualitative detection of the NSAIDs diclofenac and ibuprofen in the hair of Eurasian otters (Lutra lutra) occupying UK waterways with GC–MS

The pervasiveness of pharmaceuticals such as nonsteroidal anti-inflammatory drugs (NSAIDs) in the aquatic ecosystem through the discharge of wastewater, and their potential to biomagnify within this ecosystem, is now recognised. Residues of diclofenac and ibuprofen are currently being detected in surface waters and aquatic organisms throughout the UK and Europe. However, the levels of these residues in fish and other aquatic organisms, particularly lower trophic level prey species, have not yet been determined. While exposure to diclofenac is known to adversely affect fish, the degree to which other aquatic organisms are exposed and impacted through continuous ingestion of contaminated prey and interaction with the aquatic habitat remains unknown. The extent and effects of exposure to ibuprofen also remain largely unknown. As an exploratory subset of a broader study to investigate the detectability of diclofenac in alternative biological matrices, we analysed hair samples from Eurasian otters (Lutra lutra, n = 28) for residues of the two NSAIDs using GC–MS. The otters were collected from six counties in England as part of an ongoing otter health monitoring project at the Wildlife Veterinary Investigation Centre in Chacewater, UK. Diclofenac was qualitatively detected in five hair wash and 15 extract samples, and ibuprofen was determined to be present in at least two of the hair extract samples. Here, we provide preliminary evidence that otters are exposed to both NSAIDs and argue for further studies to identify residue loads in the otters and their prey to fully assess the pervasiveness of these compounds and potential risks of ongoing exposure to them.

Do highly modified landscapes favour generalists at the expense of specialists? An example using woodland birds

Abstract Demands on land use in heavily populated landscapes create mosaic structures where semi-natural habitat patches are generally small and dominated by edges. Small patches are also more exposed and thus more vulnerable to adverse weather and potential effects of climate change. These conditions may be less problematic for generalist species than for specialists. Using insectivorous woodland birds (great tits and blue tits) as an example, we demonstrate that even generalists suffer reduced breeding success (in particular, rearing fewer and poorer-quality young) and increased parental costs (daily energy expenditure) when living in such highly modified secondary habitats (small woods, parks, farmland). Within-habitat heterogeneity (using the example of Monks Wood NNR) is generally associated with greater species diversity, but to benefit from heterogeneity at a landscape scale may require both high mobility and the ability to thrive in small habitat patches. Modern landscapes, dominated by small, modified and scattered habitat patches, may fail to provide specialists, especially sedentary ones, with access to sufficient quantity and quality of resources, while simultaneously increasing the potential for competition from generalists.

What problems do local habitat change represent for the constant effort site ringing scheme

A mist‐netting site at Cow Lane Gravel Pits, Cambridgeshire, contributes to the British Trust for Ornithologys (BTO) Constant Effort Site (CES) ringing scheme. Standard net sites are located in relatively stable osier scrub Salix, but the nearby habitat is subject to rapid change which has resulted from the restoration of a gravel pit. This study addresses the question of whether this local habitat change results in fluctuations in the CES catch at Cow Lane which deviate from the national trends. CES catches of passerines in mist‐nets from 1989 to 1996 at Cow Lane are compared to the national trends as identified by the BTO. Most species have experienced increases and decreases at Cow Lane in accordance with the national trends, and appear to be relatively insensitive to local habitat changes. Sedge Warblers Acrocephalus schoenobaenus and Reed Warblers A. scirpaceus are the notable exceptions. Mist‐netting with additional nets in the adjacent habitat suggests that these species are responding to local expansion of wetland vegetation, and changes in the catch reflect localized changes in habitat use.

Measuring passerine productivity using constant effort sites: the effect of missed visits

Site visits for the Constant Effort Sites (CES) ringing scheme are occasionally missed and the standard 12 scheduled annually (May‐August) may not all be completed. To account for this, total annual adult and juvenile passerine catches may be adjusted for inclusion in CES productivity‐indexing analyses. Adjustment methods and the inclusion of adjusted catches are thought not to generate unrepresentative measures of productivity, but we aimed to test this. Productivity‐indexing analyses were carried out using CES data with and without adjusted catches, and long‐ and short‐term changes in productivity were compared. Similarity between productivity indices (and also the precision of estimates) was consistently high between adjusted and unadjusted data, but greatest for species caught most frequently. The inclusion of data adjusted for missed visits increases the precision of measures of productivity by increasing sample sizes, although this improvement is likely to be exaggerated as no account is taken of the uncertainty in the data adjustment. We consider adjustment methods to be appropriate, despite a great potential for between‐year variation in the seasonal pattern of catches on CE sites.

First detection of an NSAID, flunixin, in sheep’s wool using GC–MS

Exposure to the nonsteroidal anti-inflammatory drug (NSAID) diclofenac resulted in the near extinction of three species of Gyps vultures on the Indian subcontinent. Other NSAIDs present in the environment, including flunixin, may pose a similar risk. In the course of a study to determine the feasibility of detecting NSAIDs in keratinous matrices (i.e., hair, nails and feathers) using GC-MS, wool opportunistically collected from a sheep treated with flunixin was analysed for residues. Flunixin was detected qualitatively in external wool wash and extract samples. While residues of veterinary agents and pesticides have previously been found in sheeps wool, our preliminary investigation provides the first instance of an NSAID being detected in this matrix. Here we provide the sample preparation methods and GC-MS parameters used to enable further refinement as part of ongoing conservation and consumer quality control measures.

Fisheries as a source of marine debris on beaches in the United Kingdom

Marine debris from ships has persisted and remains a concern despite international agreements such as MARPOL. We report on an analysis of beach litter based on a data set established by the Marine Conservation Society (MSC) Beachwatch weekends. Debris collected around the UK was divided into three main types of debris: (1) plastic, (2) fishing, and (3) fishing related plastic and rubber. Correspondence analysis (CA) was used to examine patterns in the occurrence of debris types on a total of 1023 beaches and debris attributable to fishing was identified on clusters of beaches mainly located on the coasts of Scotland and along the English Channel. General Linear model (GLM) identified fishing as the highest explanatory factor when testing for relationships between litter and proximity to fishing ports and grounds. The results add to the growing body of evidence that the fishing industry is largely responsible for marine debris.

Observations of the under-described avifauna of the Mostardas Peninsula, Rio Grande do Sul, Brazil

The Mostardas Peninsula on the east coast of Rio Grande do Sul state, Southern Brazil is important for migratory shorebirds that depend upon the wetlands in the Lagoa do Peixe National Park. However, previous surveys have suggested that the Peninsula is bereft of terrestrial birds relative to similar habitat in Rio Grande do Sul. We used rapid assessment methods to evaluate terrestrial bird diversity and note observations of migratory birds at the western margin of Lagoa do Peixe National Park between 11 February 2007 and 25 March 2007. We recorded fourteen species not previously reported for this area, including several new breeding records, and detail the occurrence of mixed-species foraging flocks in fragmented woodland. We discuss the reasons for the discrepancy between our observations of the terrestrial avifauna and previous reports, and the possibility that the Mostardas Peninsula is a passerine migratory route that remains poorly documented.