Rufus B. Sage

Lead exposure in ring-necked pheasants on shooting estates in Great Britain

Abstract Although a few isolated incidences of lead shot ingestion have been reported in ring-necked pheasants (Phasianus colchicus) in Great Britain, no studies have investigated the prevalence of shot ingestion in this species. In this study we investigated the extent of lead exposure in ring-necked pheasants on shooting estates in Great Britain from the ingestion of shot and other sources through gizzard examinations and analysis of wing bones. We examined 437 ring-necked pheasant gizzards collected from birds shot on 32 shooting estates during spring 1996 and 1997 and during the hunting seasons of 1999–2000 and 2001–2002. We determined wing-bone-lead concentrations in 98 female birds collected in 1997. Gizzard examinations showed an overall ingestion incidence rate of 3.0%. We found no differences in ingestion rates among years, seasons, and sexes. Female pheasants had bone-lead levels ranging from 7–445 ppm (x̄ =48.8± 8.8) dry weight. The birds that had lead in their gizzards in 1997 also had high concentrations of lead in their bones. Female pheasant body condition did not decline with the amount of lead in the wing bones. Our data suggest that game managers on shooting estates should be aware that pheasants are vulnerable to shot ingestion and may need to consider measures to reduce this problem in areas where prevalence is high.

Effects of spring supplementary feeding on population density and breeding success of released pheasants Phasianus colchicus in Britain

Abstract The release of hand-reared ring-necked pheasants Phasianus colchicus in summer is a common practice in Britain to increase the number of birds available to hunters in winter. The breeding success of the birds which survive the shooting season is poor. Traditionally, birds are provided with supplementary wheat grain from release until the end of the shooting season (1 February) to maintain body condition and to help hold birds in areas for hunting. During 1997–2000 we assessed the effect of continuing supplementary feeding into spring on pheasant density and breeding success on seven private shooting estates. On each estate we randomly selected two distinct 1-km2 plots and provided wheat grain via feed hoppers for birds in breeding territories in one of the plots on each estate while the other plot acted as an untreated control. Food was provided from mid-February to mid-May. We crossed-over the treatment and control plot on each estate each year. We conducted pre- and post-breeding pheasant counts in the plots during April and September. During April, densities were higher in treatment plots than in control plots for territorial males: (mean ± SE) treatment = 22.6 ± 1.5 birds/km2, control = 14.8 ± 1.2 birds/km2, (P < 0.001) and for females: treatment = 40.6 ± 5.8 birds/km2, control = 24.1 ± 3.8 birds/km2 (P < 0.001). In September we found no statistical effect of treatment on densities of adult birds or on brood size. However, more young were observed on treatment plots: 10.8 ± 1.5 birds/km2, than in control plots: 5.6 ± 1.0 birds/km2, (P = 0.02). In order to improve the breeding potential of released pheasants, we recommend that spring supplementary feeding is undertaken on shooting estates in Britain.

Post hibernation dispersal of three leaf-eating beetles (Coleoptera: Chrysomelidae) colonising cultivated willows and poplars

1 We studied the spring dispersal of three common chrysomelids, from overwintering habitats into cultivated willow and poplar coppices at four sites in southern England over 2 years.

Dedicated biomass crops can enhance biodiversity in the arable landscape

Suggestions that novel, non‐food, dedicated biomass crops used to produce bioenergy may provide opportunities to diversify and reinstate biodiversity in intensively managed farmland have not yet been fully tested at the landscape scale. Using two of the largest, currently available landscape‐scale biodiversity data sets from arable and biomass bioenergy crops, we take a taxonomic and functional trait approach to quantify and contrast the consequences for biodiversity indicators of adopting dedicated biomass crops on land previously cultivated under annual, rotational arable cropping. The abundance and community compositions of biodiversity indicators in fields of break and cereal crops changed when planted with the dedicated biomass crops, miscanthus and short rotation coppiced (SRC) willow. Weed biomass was consistently greater in the two dedicated biomass crops than in cereals, and invertebrate abundance was similarly consistently higher than in break crops. Using canonical variates analysis, we identified distinct plant and invertebrate taxa and trait‐based communities in miscanthus and SRC willows, whereas break and cereal crops tended to form a single, composite community. Seedbanks were shown to reflect the longer term effects of crop management. Our study suggests that miscanthus and SRC willows, and the management associated with perennial cropping, would support significant amounts of biodiversity when compared with annual arable crops. We recommend the strategic planting of these perennial, dedicated biomass crops in arable farmland to increase landscape heterogeneity and enhance ecosystem function, and simultaneously work towards striking a balance between energy and food security.

Diet complexity in early life affects survival in released pheasants by altering foraging efficiency, food choice, handling skills and gut morphology

Behavioural and physiological deficiencies are major reasons why reintroduction programmes suffer from high mortality when captive animals are used. Mitigation of these deficiencies is essential for successful reintroduction programmes. Our study manipulated early developmental diet to better replicate foraging behaviour in the wild. Over 2 years, we hand-reared 1800 pheasants (Phasianus colchicus), from 1 day old, for 7 weeks under different dietary conditions. In year one, 900 pheasants were divided into three groups and reared with (i) commercial chick crumb, (ii) crumb plus 1% live mealworm or (iii) crumb plus 5% mixed seed and fruit. In year two, a further 900 pheasants were divided into two groups and reared with (i) commercial chick crumb or (ii) crumb plus a combination of 1% mealworm and 5% mixed seed and fruit. In both years, the commercial chick crumb acted as a control treatment, whilst those with live prey and mixed seeds and fruits mimicking a more naturalistic diet. After 7 weeks reared on these diets, pheasants were released into the wild. Postrelease survival was improved with exposure to more naturalistic diets prior to release. We identified four mechanisms to explain this. Pheasants reared with more naturalistic diets (i) foraged for less time and had a higher likelihood of performing vigilance behaviours, (ii) were quicker at handling live prey items, (iii) were less reliant on supplementary feed which could be withdrawn and (iv) developed different gut morphologies. These mechanisms allowed the pheasants to (i) reduce the risk of predation by reducing exposure time whilst foraging and allowing more time to be vigilant; (ii) be better at handling and discriminating natural food items and not be solely reliant on supplementary feed; and (iii) have a better gut system to cope with the natural forage after the cessation of supplementary feeding in the spring. Learning food discrimination, preference and handling skills by the provision of a more naturalistic diet is essential prior to the release of pheasants in a reintroduction programme. Subsequent diet, foraging behaviour, gut morphology and digestive capabilities all work together as one nutritional complex. Simple manipulations during early development can influence these characteristics to better prepare an individual for survival upon release.

Impact of roe deer Capreolus capreolus browsing on understorey vegetation in small farm woodlands

The impact of around nine roe deer Capreolus capreolus!km2 on ground and shrub vegetation was assessed in a sample of six small woodlands on a largely arable estate in Dorset, southern England. In January 1996, 30 exclosures of 2 × 2 × 1.5 m and 30 paired controls were set up. Measurements of vegetation density at six height categories using a cover board were taken in late winter and mid-summer in each of the four years 1996–1999. Mean cover values were calculated for each woodland, and they indicated that the density of vegetative cover was reduced by deer browsing in winter and in summer. The effect of the browsing increased significantly within the four-year study period, and plant species composition had changed by the end of the study period. Our results suggest that roe deer may be having a substantial and potentially widespread effect on vegetative structure and composition in small farm woodlands in arable ecosystems in central southern England. The implications of this, for the characteristic wildlife and game species found in this common woodland habitat, are discussed.

Multiple behavioural, morphological and cognitive developmental changes arise from a single alteration to early life spatial environment, resulting in fitness consequences for released pheasants

Subtle variations in early rearing environment influence morphological, cognitive and behavioural processes that together impact on adult fitness. We manipulated habitat complexity experienced by young pheasants (Phasianus colchicus) in their first seven weeks, adding a third accessible dimension by placing elevated perches in their rearing pens mimicking natural variation in habitat complexity. This simple manipulation provoked an interrelated suite of morphological, cognitive and behavioural changes, culminating in decreased wild mortality of birds from complex habitats compared with controls. Three mechanisms contribute to this: Pheasants reared with perches had a morphology which could enable them to fly to the higher branches and cope with prolonged roosting. They had a higher propensity to roost off the ground at night in the wild. More generally, these birds had more accurate spatial memory. Consequently, birds were at a reduced risk of terrestrial predation. The fitness consequences of variation in early rearing on behavioural development are rarely studied in the wild but we show that this is necessary because the effects can be broad ranging and not simple, depending on a complex interplay of behavioural, cognitive and morphological elements, even when effects that the treatments provoke are relatively short term and plastic.

The efficacy of a technique to control parasitic worm burden in pheasants (Phasianus colchicus) in the wild

SummaryThe lower productivity of reared pheasants (Phasianus colchicus) compared to their wild counterparts is well documented. Providing supplementary food for pheasants throughout the spring has been shown to increase their breeding success, primarily through improving hen body condition. In a separate study, individually dosing hens with an anthelminthic in spring to reduce their parasitic worm burden has also been shown to increase their productivity in the wild. In a small-scale pilot study these two techniques were combined to test their efficacy as a means of treating free-living pheasants in spring without the need to catch individuals. The parasitic worms recorded wereHeterakis gallinarum andCapillaria spp., both of which are found in the caecae. The results indicated that, in the absence of anthelminthic treatment, worm burden in pheasants increased rapidly between March and April, but in contrast, birds given anthelminthic treated grain had significantly lower worm burden during the same period. Therefore we suggest that this is an effective management technique for treating freeliving pheasants in spring. Subsequently, an experiment was carried out to try to assess the best time to allow pheasants access to ‘treated’ grain in the wild in order to maximise its benefits. Hen pheasants in pens were exposed to infection from the soil. Specific groups of hens were ‘dosed’ at three weekly intervals with anthelminthic treated food and their worm burdens recorded when they were killed at various times thereafter. The results were not clear cut, but suggested that dosing as late as possible prior to nesting would be most beneficial to the hens.ZusammenfassungDie geringere Produktivität gezüchteter Fasanen (Phasianus colchicus) im Vergleich zu wild lebenden ist gut belegt. Durch Fütterung von Fasanen im Frühjahr wurde der Bruterfolg erhöht, hauptsächlich wegen der verbesserten körperlichen Kondition der Hennen. Eine weitere Studie ergab, dass die individuelle Behandlung von Hennen mit Anthelminthika, mit dem Ziel einer Reduktion der Wurmbürde, ebenfalls den Fortpflanzungserfolg steigerte. In einer kleinräumigen Pilotstudie wurden diese beiden Methoden kombiniert, um ihre Wirksamkeit für die Behandlung frei lebender Fasane im Frühjahr, ohne die Notwendigkeit des Fangs der Tiere, zu prüfen. Als parasitische Würmer wurden im BlinddarmHeterakis gallinarum undCapillaria spp. nachgewiesen. Die Ergebnisse zeigten, dass ohne Anthelminthika-Behandlung die Wurmbürde der Fasane zwischen März und April deutlich zunahm. Im Gegensatz dazu, wiesen Fasanen, die mit Anthelminthika-behandeltem Getreide gefüttert worden waren, im gleichen Zeitraum eine signifikant niedrigere Wurmbürde auf. Wir empfehlen diese Methode daher als wirksames Verfahren zur Behandlung frei lebender Fasane im Frühjahr. In einem nachfolgenden Experiment wurde versucht, den optimalen Zeitpunkt für die Darreichung von behandeltem Futter im Freiland zu ermitteln. Dazu wurden Fasanenhennen im Gehege einer Wurminfektion über den Boden ausgesetzt. Einzelnen Gruppen von Hennen wurde in dreiwöchigen Abständen Anthelminthika-behandeltes Futter verabreicht. Die Tiere wurden anschlie\end zu verschiedenen Zeitpunkten getötet und ihre Wurmbürde bestimmt. Die Ergebnisse waren nicht eindeutig, deuteten aber darauf hin, dass die Verabreichung des behandelten Futters so kurz wie möglich vor Beginn der Nistzeit am günstigsten für die Hennen ist.

Assessing breeding success in common woodland birds using a novel method

Capsule Repeated counts of fledged broods can provide a useful estimate of breeding success for most common woodland birds. Aims To assess the efficacy of comparing fledged-brood survey data with territory mapping using simple mark–recapture analysis techniques to provide an estimate of breeding success for common woodland birds that does not involve finding nests. Methods Three observers undertook territory mapping surveys of adults, followed by counts of fledged broods four times a week during May–July 2007 in two 15 ha woods each, both in southern England. Using known fledging to maturity periods, these counts were used to calculate daily detection probabilities for broods of ubiquitous species. These enabled fledged brood territory occupancy probabilities (i.e. brood to territory ratios) to be estimated that take account of the possibility that broods were present but missed by surveys. Results Of the 19 species found in all six woods, mean daily detection probability estimates for fledged broods of 17 species ranged from 0.17 to 0.50 with significant variation between woods for 12 species, but within region/observer for four species. The mean probability of detecting a brood at least once was over 75% using four visits per week and over 50% using two visits. Only for Great Spotted Woodpeckers Dendrocopos major and Garden Warblers Sylvia borin was the fledging period too short and the daily detection probability too low to provide a reasonable estimate of the territory occupancy probability. Conclusion Daily detection probabilities for fledged broods of most common woodland birds were sufficiently high to enable useable estimates of fledged-brood territory occupancy probabilities to be made based on a survey programme involving two or three visits per week between late May and the end June. The method used may have application as a means of providing a relatively easily derived productivity index for woodland bird monitoring programmes or for research studies.

Bird use of establishment-stage Miscanthus biomass crops during the breeding season in England

Capsule Summer bird densities in establishment-stage (2–3-year-old) Miscanthus were the same as in winter wheat fields for many species, but were higher for Lapwing, and for Reed Bunting and Blackbird late in the summer. Aims To compare abundances of farmland birds in establishment-stage Miscanthus biomass crops with those in crop types they are likely to replace (winter wheat and grassland) during the breeding season. In particular, to investigate whether such a rapid-growing, dense crop has lower abundances of field-nesting species. Methods Bird surveys were conducted in 51 Miscanthus fields and an equal number of grass or winter wheat control fields between May and July, in Lincolnshire and southwest England. Results Species richness was similar in Miscanthus to that in winter wheat and grass. Skylark densities were similar in Miscanthus and wheat, while Lapwing densities were higher in Miscanthus and grass than wheat. Miscanthus contained very high densities of Reed Buntings and Blackbirds late in the summer. Conclusion Densities of most bird species, including field-nesting species, were not lower in establishment-stage Miscanthus than in the crops it most commonly replaced. The Miscanthus surveyed was relatively weedy and patchy; further studies as crops age and knowledge of Miscanthus husbandry increases would be valuable.