Stable isotope analysis provides new information on winter habitat use of declining avian migrants that is relevant to their conservation

Winter habitat use and the magnitude of migratory connectivity are important parameters when assessing drivers of the marked declines in avian migrants. Such information is unavailable for most species. We use a stable isotope approach to assess these factors for three declining African-Eurasian migrants whose winter ecology is poorly known: wood warbler Phylloscopus sibilatrix, house martin Delichon urbicum and common swift Apus apus. Spatially segregated breeding wood warbler populations (sampled across a 800 km transect), house martins and common swifts (sampled across a 3,500 km transect) exhibited statistically identical intra-specific carbon and nitrogen isotope ratios in winter grown feathers. Such patterns are compatible with a high degree of migratory connectivity, but could arise if species use isotopically similar resources at different locations. Wood warbler carbon isotope ratios are more depleted than typical for African-Eurasian migrants and are compatible with use of moist lowland forest. The very limited variance in these ratios indicates specialisation on isotopically restricted resources, which may drive the similarity in wood warbler populations' stable isotope ratios and increase susceptibility to environmental change within its wintering grounds. House martins were previously considered to primarily use moist montane forest during the winter, but this seems unlikely given the enriched nature of their carbon isotope ratios. House martins use a narrower isotopic range of resources than the common swift, indicative of increased specialisation or a relatively limited wintering range; both factors could increase house martins' vulnerability to environmental change. The marked variance in isotope ratios within each common swift population contributes to the lack of population specific signatures and indicates that the species is less vulnerable to environmental change in sub-Saharan Africa than our other focal species. Our findings demonstrate how stable isotope research can contribute to understanding avian migrants' winter ecology and conservation status

Pollutants Increase Song Complexity and the Volume of the Brain Area HVC in a Songbird

Environmental pollutants which alter endocrine function are now known to decrease vertebrate reproductive success. There is considerable evidence for endocrine disruption from aquatic ecosystems, but knowledge is lacking with regard to the interface between terrestrial and aquatic ecosystems. Here, we show for the first time that birds foraging on invertebrates contaminated with environmental pollutants, show marked changes in both brain and behaviour. We found that male European starlings (Sturnus vulgaris) exposed to environmentally relevant levels of synthetic and natural estrogen mimics developed longer and more complex songs compared to control males, a sexually selected trait important in attracting females for reproduction. Moreover, females preferred the song of males which had higher pollutant exposure, despite the fact that experimentally dosed males showed reduced immune function. We also show that the key brain area controlling male song complexity (HVC) is significantly enlarged in the contaminated birds. This is the first evidence that environmental pollutants not only affect, but paradoxically enhance a signal of male quality such as song. Our data suggest that female starlings would bias their choice towards exposed males, with possible consequences at the population level. As the starling is a migratory species, our results suggest that transglobal effects of pollutants on terrestrial vertebrate physiology and reproduction could occur in birds

Parental self-feeding effects on parental care levels and time allocation in Palestine sunbirds.

The trade-off between parents feeding themselves and their young is an important life history problem that can be considered in terms of optimal behavioral strategies. Recent studies on birds have tested how parents allocate the food between themselves and their young. Until now the effect of food consumption by parent birds on their food delivery to their young as well as other parental activities has rarely been studied. I have previously shown that parent Palestine sunbirds (Nectarinia osea) will consume nectar and liquidized arthropods from artificial feeders. However, they will only feed their young with whole arthropods. This provided a unique opportunity to experimentally manipulate the food eaten by parents independent of that fed to their offspring. Here, I hypothesized that parents invest in their current young according to the quality of food that they themselves consume. Breeding pairs with two or three nestlings were provided with feeders containing water (control), sucrose solution (0.75 mol) or liquidized mealworms mixed with sucrose solution (0.75 mol). As food quality in feeders increased (from water up to liquidized mealworms mixed with sucrose solution): 1) Parents (especially females) increased their food delivery of whole arthropod prey to their young. 2) Only males increased their nest guarding effort. Nestling food intake and growth rate increased with increasing food quality of parents and decreasing brood size. These results imply that increasing the nutrient content of foods consumed by parent sunbirds allow them to increase the rate at which other foods are delivered to their young and to increase the time spent on other parental care activities

Pollutants affect development in nestling starlings Sturnus vulgaris

1. Pollutants as endocrine disrupting chemicals (EDCs) are of worldwide concern, due to their detrimental effects on the physiology and behaviour of wildlife. One major source of EDCs is sewage treatment works which serve as foraging grounds for many bird species. However, the risks of consuming EDCs to wild birds at these sites have been largely overlooked. 2. We have previously quantified contamination levels of invertebrates fromwithin filter beds of sewage treatment works and the intake rates of these invertebrates by wild European starlings feeding at these sites. Our work to date has shown that environmentally-relevant EDC exposure results in reduced immunocompetence, increased song behaviour and neural development in adult starlings. 3. In the present study, we hypothesized that nestling starlings exposed to similar EDC levels from contaminated prey, from parental feeding at sewage treatment works, would show altered growth and physiology. 4. Our findings show that EDC exposure results in reduced growth and immunocompetence in nestling birds. However, there was no effect on corticosterone or haematocrit levels. As growth rates and immunocompetence are likely to be related to survival rates, we suggest that these exposure levels are likely to adversely affect recruitment into the adult population. 5. Synthesis and applications. These results highlight the potential transfer of EDCs between semiaquatic or aquatic organisms and terrestrial organisms up the food chain at sites of sewage treatment works, broadening the scope of potential routes of exposure. Our findings suggest that birds foraging in these sites are at risk of physiological manipulation from EDCs and reduced body condition as a result. We advocate further work to evaluate the potential for EDCs from sewage treatment works to bioaccumulate and modulate the condition of wild organisms feeding on contaminated prey. Our results suggest that changes in management practices of sewage treatment works are required. We support measures to reduce EDC levels in sewage treatment works and that these sites should be designed to exclude or deter wildlife from foraging on contaminated prey. The management implications of such policy – oriented steps will ensure the health of wildlife foraging at sewage treatment works

clout

clout_means_ a blow (physical stroke, not a wind). clout _means_ cloth, esp. in _dish_ -clout. clouts _means_ clothes (plural), especially disparagingly, e.g. "She only left her daughter a few auld clouts" - referring to a bequest of used or poor clothes.JH-1-12-69Not usedNot usedWithdrawnChecked by Jordyn Hughes on Wed 20 Jul 201

Palestine sunbird mean nestling mass at 13 days of age (means ± SE) plotted against brood size (2 or 3 nestlings), and quality of food available in an artificial feeder, which was either water (Water), sucrose solution (Sugar) or sucrose and mealworm solution (Sugar and worms).

<p>Palestine sunbird mean nestling mass at 13 days of age (means ± SE) plotted against brood size (2 or 3 nestlings), and quality of food available in an artificial feeder, which was either water (Water), sucrose solution (Sugar) or sucrose and mealworm solution (Sugar and worms).</p

ANOVA results for parental care levels and nestlings growth measurements in Palestine sunbirds: a) mean parental visits per nestling per hour; b) mean nestling mass, c) mean nestling bill length, d) mean nestling tarsus length at the end of the manipulation (day 13). The effects of food content in an artificial feeder (Food), and brood size (Brood) are given. Results of ANOVA models are presented with <i>df</i>, MS, F-ratios, and P-values.

<p>ANOVA results for parental care levels and nestlings growth measurements in Palestine sunbirds: a) mean parental visits per nestling per hour; b) mean nestling mass, c) mean nestling bill length, d) mean nestling tarsus length at the end of the manipulation (day 13). The effects of food content in an artificial feeder (Food), and brood size (Brood) are given. Results of ANOVA models are presented with <i>df</i>, MS, F-ratios, and P-values.</p

Time spent mobbing near the nest per hour (means ± SE) by Palestine sunbirds plotted against brood size (2 or 3 nestlings), quality of food available in an artificial feeder, which was either water (Water), sucrose solution (Sugar) or sucrose and mealworm solution (Sugar and worms), and parental sex (blank: males; cross hatched: females).

<p>The values consist of the average for the whole seven days of the manipulation period (from nestlings being 7 days of age until 13 days of age) for each parent.</p

The effects of the experimental feeder food solution (Food), brood size (Brood) and parental sex (Sex) in Palestine sunbirds on (a) the mean time that was spent feeding at a feeder per hour, and (b) the mean volume of food solution consumed per hour. The results of the ANOVA models are presented with <i>df</i>, MS, F- ratios, and P-values.

<p>The effects of the experimental feeder food solution (Food), brood size (Brood) and parental sex (Sex) in Palestine sunbirds on (a) the mean time that was spent feeding at a feeder per hour, and (b) the mean volume of food solution consumed per hour. The results of the ANOVA models are presented with <i>df</i>, MS, F- ratios, and P-values.</p

ANOVA results for: (a) mean parental visit rates per hour; (b) mean time spent at the nest per parental visit; (c) mean time spent mobbing near the nest per hour, in Palestine sunbirds. The effects of food content in an artificial feeder (Food), brood size (Brood), and parental sex (Sex) are given. The results of the ANOVA models are presented with <i>df</i>, MS, F-ratios, and P-values.

<p>ANOVA results for: (a) mean parental visit rates per hour; (b) mean time spent at the nest per parental visit; (c) mean time spent mobbing near the nest per hour, in Palestine sunbirds. The effects of food content in an artificial feeder (Food), brood size (Brood), and parental sex (Sex) are given. The results of the ANOVA models are presented with <i>df</i>, MS, F-ratios, and P-values.</p