Tamarisk biocontrol using Tamarisk Beetles: Potential consequences for riparian birds in the southwestern United Stains

The tamarisk beetle (Diorhabda spp.), a non-native biocontrol agent, has been introduced to eradicate tamarisk (Tamarix spp.), a genus of non-native tree that has become a dominant component of riparian woodlands in the southwestern United States. Tamarisk beetles have the potential to spread widely and defoliate large expanses of tamarisk habitat, but the effects of such a widespread loss of riparian vegetation on birds remains unknown. We reviewed literature on the effects of other defoliating insects on birds to investigate the potential for tamarisk beetles to affect birds positively or negatively by changing food abundance and vegetation structure. We then combined data on the temporal patterns of tamarisk defoliation by beetles with nest productivity of a well studied riparian obligate, the Southwestern Willow Flycatcher (Empidonax traillii extimus), to simulate the potential demographic consequences of beetle defoliation on breeding riparian birds in both the short and long term. Our results highlight that the effects of tamarisk biocontrol on birds will likely vary by species and population, depending upon its sensitivity to seasonal defoliation by beetles and net loss of riparian habitat due to tamarisk mortality. Species with restricted distributions that include areas dominated by tamarisk may be negatively affected both in the short and long term. The rate of regeneration and/or restoration of native cottonwoods (Populus spp.)and willows (Salix spp.) relative to the rate of tamarisk loss will be critical in determining the long-term effect of this large-scale ecological experiment

Bird Feeders as Locations for Skunk Uptake of Oral Rabies Vaccine Baits

Significantly more (54%, P=0.003) placebo baits placed under 26 bird feeders in Arizona, US were removed by striped skunks (Mephitis mephitis) than at paired, nonfeeder locations (19%). Baiting at bird feeders could supplement traditional oral rabies vaccine bait placement in urban-suburban areas while engaging the public in rabies control efforts

Age, habitat, and yearly variation in the diet of a generalist insectivore, the Southwestern Willow Flycatcher

The article presents a study which examines the age, habitat, and yearly variation in the diet of a generalist insectivore, the southwestern Willow Flycatcher at Roosevelt Lake in central Arizona. It focuses on the five prey categories which were accounted for 70% of the proportional abundance in flycatcher diet, including Hymenoptera, Diptera, Cicadellidae, Coleoptera, and Formicide. It states that there were no detected differences in diet between sexes of adults, but adults and nestling samples differed, with higher proportions of Hymenoptera in adult samples and more Diptera in nestling samples. It discusses the comparison between flycatcher diet in habitat patches dominated by native cottonwood and willow, exotic salt cedar, or a mix of the three species

Variation in prey delivered to common Black-Hawk (Buteogallus anthracinus) nests in Arizona drainage basins

Understanding how raptor diets vary across local and regional scales can be important when human actions have the potential to alter prey abundances. We combined data on prey delivered to 16 Common Black-Hawk (Buteogallus anthracinus) nests in three tributaries of the Verde River, Arizona, in 2008 and 2009 with similar data reported previously (1994) for three other Arizona drainage basins to better understand variation in diet composition within and across drainage basins. Within the three drainage basins studied in 2008 and 2009, nests clustered into two groups: those along Fossil Creek, where fish and amphibians were common, and those in Wet Beaver and Oak Creek drainage basins, where reptiles and nonnative crayfish were more abundant. When data from all six drainage basins were combined, drainage basins again clustered into two groups, with prey deliveries in one cluster dominated by fish and amphibians and in the other cluster by reptiles. These results confirm the opportunistic nature of prey use by Common Black-Hawks and highlight the variation in diet that can occur both within and among drainage basins. Management targeting the eradication of nonnative crayfish or the reintroduction of native amphibians and fish could alter prey availability for this raptor species

Bird Feeders as Locations for Skunk Uptake of Oral Rabies Vaccine Baits

Significantly more (54%, P=0.003) placebo baits placed under 26 bird feeders in Arizona, US were removed by striped skunks (Mephitis mephitis) than at paired, nonfeeder locations (19%). Baiting at bird feeders could supplement traditional oral rabies vaccine bait placement in urban-suburban areas while engaging the public in rabies control efforts