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1.  Is sociality associated with high longevity in North American birds? 
Biology Letters  2008;4(2):146-148.
Sociality, as a life-history trait, should be associated with high longevity because complex sociality is characterized by reproductive suppression, delayed breeding, increased care and survival, and some of these traits select for high longevity. We studied the relationship between cooperative parental care (a proxy of complex sociality) and relative maximum lifespan in 257 North American bird species. After controlling for variation in maximum lifespan explained by body mass, sampling effort, latitude, mortality rate, migration distance and age at first reproduction, we found no significant effect of cooperative care on longevity in analyses of species-specific data or phylogenetically independent standardized linear contrasts. Thus, sociality itself is not associated with high longevity. Rather, longevity is correlated with increased body size, survival rate and age of first reproduction.
PMCID: PMC2429933  PMID: 18182364
cooperative breeding; life-history theory of senescence; longevity; maximum lifespan
2.  Anecdotes and empirical research in Chernobyl 
Biology Letters  2007;4(1):65-66.
PMCID: PMC2412943
3.  Species richness and abundance of forest birds in relation to radiation at Chernobyl 
Biology Letters  2007;3(5):483-486.
The effects of low-level radiation on the abundance of animals are poorly known, as are the effects on ecosystems and their functioning. Recent conclusions from the UN Chernobyl forum and reports in the popular media concerning the effects of radiation from Chernobyl on animals have left the impression that the Chernobyl exclusion zone is a thriving ecosystem, filled with an increasing number of rare species. Surprisingly, there are no standardized censuses of common animals in relation to radiation, leaving the question about the ecological effects of radiation unresolved. We conducted standardized point counts of breeding birds at forest sites around Chernobyl differing in level of background radiation by over three orders of magnitude. Species richness, abundance and population density of breeding birds decreased with increasing level of radiation, even after controlling statistically for the effects of potentially confounding factors such as soil type, habitat and height of the vegetation. This effect was differential for birds eating soil invertebrates living in the most contaminated top soil layer. These results imply that the ecological effects of Chernobyl on animals are considerably greater than previously assumed.
PMCID: PMC2394539  PMID: 17698449
census; ecosystem effects; population density; radiation at Chernobyl; species richness
4.  Elevated frequency of abnormalities in barn swallows from Chernobyl 
Biology Letters  2007;3(4):414-417.
Ever since the Chernobyl accident in 1986, that contaminated vast areas in surrounding countries with radiation, abnormalities and birth defects have been reported in human populations. Recently, several studies suggested that the elevated frequency of such abnormalities can be attributed to poverty and stress in affected human populations. Here, we present long-term results for a free-living population of barn swallows, Hirundo rustica, demonstrating the presence of 11 morphological abnormalities in populations around Chernobyl, but much less frequently in an uncontaminated Ukrainian control population and three more distant control populations. The presence of these abnormalities in barn swallows is associated with reduced viability. These findings demonstrate a link between morphological abnormalities and radiation in an animal population that cannot be attributed to poverty and stress. The most parsimonious hypothesis for abnormalities in animal and human populations alike is that the effects are caused by the same underlying cause, viz. radiation derived from the Chernobyl accident.
PMCID: PMC1994720  PMID: 17439847
Hirundo rustica; mutation; radiation; viability

Results 1-4 (4)