Characteristics of aspen infected with heartrot: Implications for cavity-nesting birds

Phellinus tremulae is an important fungal decay agent common to aspen and a critical component to the cavity-nesting bird complex found in western aspen stands. Little information exists on the conditions that facilitate infection and spread of P. tremulae in aspen forests. I used Forest Inventory and Analysis (FIA) data to explore the relationships of several tree and stand characteristics to the presence and frequency of P. tremulae in aspen measured across several western states of the United States. Results suggest a strong relationship between tree age, tree diameter, and compacted crown ratio with infection frequency in trees while stand purity, canopy cover and stand age had a positive relationship with the occurrence of P. tremulae in forest stands containing aspen. Logistic regression modeling identified stand age as the only variable that increased the odds of predicting infection at the stand-level while all tree-level variables were included in the tree model. Data also show that infection rates in the study area were lower than in other parts of aspen's range, and that average size of infected trees was smaller in the study area than those reported elsewhere. These results have important implications to management of aspen for wildlife, especially for birds that use decayed aspen for nesting.     

Does afforestation increase bird nest predation risk in surrounding farmland?

Afforestation of agricultural land is increasingly used to deliver environmental benefits, but their effects on biodiversity remain poorly understood. This paper tests the hypothesis that afforestation changes predation processes in surrounding farmland, examining how the characteristics and landscape context of forest plantations affect predator (birds and mammalian carnivores) and key prey (rabbits and hares) abundances, and bird nest predation rates in Iberian cereal-steppes. Lagomorphs and predators were surveyed in fallow fields around 50 forest plantations, where predation rates were estimated using artificial nests set at 0, 100, 200 and 300 m from the forest edge. Recent plantations structurally similar to sparse (oak) or dense (pine) shrublands were associated with the highest hare and rabbit abundances, respectively, whereas both species avoided landscapes with high eucalyptus cover. In contrast, mature eucalyptus plantations showed strong positive effects on typical nest predators such as corvids and carnivores. Open farmland fragmentation favoured the abundance of lagomorphs and carnivores. Despite these effects and the high predation rate on artificial nests (49%), there was neither evidence for increased predation near plantation edges nor higher predation in fields with more lagomorphs and predators. However, predation tended to increase with cover by young oak plantations and overall forest plantation cover, to decrease with eucalyptus cover at both the local and landscape scales, and to peak in landscapes with intermediate edge densities. These results suggest that afforestation may have strong effects on bird nest predation rates by changing landscape composition and configuration, rather than by inducing local increases in predator and prey populations. Nevertheless, increased abundances of generalist predators associated with forest plantations may still be considered of conservation concern, thus supporting the recommendation for strongly restricting afforestation in areas important for open grassland birds. Where this is unavoidable, monitoring should be undertaken to provide early signals for bird population declines associated with predator increases, eventually triggering conservation action such as predator exclusion or removal.     

Avian foraging and nesting use of created snags in intensively-managed forests of western Oregon,USA

Snags are critical structural features for managing biological diversity in forests of the Pacific Northwest, USA. However, commercial forests in this region often contain reduced numbers of snags compared to unmanaged forests and managers require effective methods to augment snag numbers in harvest units. Therefore, we created snags by topping live trees with a mechanical harvester and studied foraging and nesting use by cavity-nesting birds of these snags in clearcuts in Douglas-fir (Pseudotsuga mensezii) forests along the west slope of the Cascade Mountain Range and east slope of the Coast Range in Oregon, USA. We used a completely randomized design to assign 6 different treatments (single or scattered distribution by 3 different densities) to 31 different harvest units. We created 1111 snags from February 1997 through April 1999 and monitored them from 2–5 years after harvest (1999–2002). Fraction of created snags with nest cavities in harvest units was generally low across all treatments and years of the study, although some individual stands demonstrated increased nesting use with snag age. While the highest fractions of snags with nest cavities were found in units with low density and scattered snags, the mean fraction of snags used for nesting did not differ among treatments. Treatment type, distribution of snags (i.e., scattered or clumped), and associated interactions did not influence fraction of snags used for foraging. However, fraction of created snags used for foraging in all harvest units increased with snag age. Fraction of snags used for foraging was greatest in the low density treatments. While this technique provides managers with a relatively economical option for creating snags, mechanical harvesters cannot be used to create tall, large snags upon which several cavity-dependent species rely and provides only a partial solution to a critical forest management issue.     

西藏“一江两河”流域越冬黑颈鹤种群数量及分布1）

对西藏“一江两河”流域越冬黑颈鹤（ Grus nigricollis）种群数量及分布情况进行了调查,并分析了黑颈鹤昼间活动生境和人为干扰情况。结果表明：2010年12月—2011年1月、2012年12月—2013年1月、2015年1月在“一江两河”流域越冬的黑颈鹤数量分别为6041、59496、496只。拉孜到南木林之间雅鲁藏布江中上游河谷和墨竹工卡到林周之间的拉萨河－澎波河谷一区是越冬黑颈鹤最为集中的2个区域;黑颈鹤昼间活动的主要生境是农田和水体,在这2种生境活动的黑颈鹤集群分别占集群总数（ n＝125）的80．8％和17．6％;12．0％的越冬黑颈鹤集群受到人为干扰的影响,其中69．2％的干扰来自开发建设。     

Characterization of seabird bycatch in eastern Canadian waters, 1998–2011, assessed from onboard fisheries observer data

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Squamous cell carcinoma of the footpad with systemic metastasis in a captive crowned solitary eagle (Buteogallus coronatus)

Squamous cell carcinomas (SCC) are one of the most common tumors of the tegument that can have a misdiagnosis of chronic skin wounds. An adult captive crowned solitary eagle presented an indolent wound-like ulcer on the footpad and a fatal outcome. An infiltrating tumoral mass in the foot and multiple tumoral metastatic nodules in visceral organs were detected. The neoplasm was composed of atypical squamous cells with strong positivity for cytokeratin, “keratin pearl” structures, and marked invasion of tissues confirming a diagnosis of metastatic SCC. This might be the first report of an SSC with metastasis on the footpad in a captive Chaco eagle, which is one of the endangered species of birds of prey.