News from Landels-Hill Big Creek Reserve
Here is a link to another article published by Terra Kelly et. al. on lead exposure.
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0017656
In this study they found that the California lead ban in the current CA condor range seems to be reducing lead exposure in turkey vultures and golden eagles. They sampled at Big Creek Reserve in 2008 & 2009.
Here is the link to the publication of lead exposure research done by Terra Kelly and Christine Johnson. http://dx.plos.org/10.1371/journal.pone.0015350
In 2008 & 2009 Terry and Christine used Big Creek Reserve as a study site to detect lead in the blood of scavenging birds. They found that lead toxicity in the blood increased during deer hunting season and was positively correlated with increasing pig hunting intensity. This work has been important in showing that the effects of lead ammunition are not isolated to California condors but involve other scavengers such as turkey vultures and golden eagles.
Here is the Abstract from their paper:
Predatory and scavenging birds are at risk of lead exposure when they feed on animals injured or killed by lead ammunition. While lead ammunition has been banned from waterfowl hunting in North America for almost two decades, lead ammunition is still widely used for hunting big game and small game animals. In this study, we evaluated the association between big game hunting and blood lead concentration in an avian scavenger species that feeds regularly on large mammals in California. We compared blood lead concentration in turkey vultures within and outside of the deer hunting season, and in areas with varying wild pig hunting intensity. Lead exposure in turkey vultures was significantly higher during the deer hunting season compared to the off-season, and blood lead concentration was positively correlated with increasing wild pig hunting intensity. Our results link lead exposure in turkey vultures to deer and wild pig hunting activity at these study sites, and we provide evidence that spent lead ammunition in carrion poses a significant risk of lead exposure to scavengers.
Wow, it’s been a year already! I know we’ve been busy, but where did the time go? We are on our way to summer and Mother Nature seems to have the best Neosporin ointment around. So many of the scars have healed and those that are left are reminders of how close we came and how far we have come.
Our Barn Swallows have recovered nicely as well. They are already on their second clutch. They don’t waste time; and they don’t coddle their first clutch. They will work very hard all day to find bugs for the babies. But when it is time to fledge, those babies better learn to fly….and fast! We have seen Swallow parents standing on top of the weakest baby, plucking feathers and poking their heads. The parents make it very clear they are done with the coddling; and that they need the nest for more babies. Those fledglings are on their own!
One afternoon, we had so many different birds with their babies in the yard. There were California Brown and Spotted Towhees, California Thrashers, Flickers and Hooded Grosbeaks. It was interesting to see so many diets and methods for obtaining food. The Thrashers and Flickers use their long beaks to dig bugs out of the ground. The Towhees like seed and cracked corn; and the Hooded Grosbeaks like the dried seed pods on the native grasses. And, flying overhead, the Turkey Vultures follow their noses to carrion on the ground.
Turkey Vultures, Cathartes aura, are not as huge and exotic as our California Condors, but they have been the subject of research for two years now at Big Creek Reserve. For two springs, scientists from the Wildlife Health Center (WHC) at the
Lenny is a friendly, male TV who was injured and nursed back to health at the WHC. He is unable to fly, and doesn’t object to being placed in a large cage/trap because he gets all the dead food he can eat. The scientists: Terra Kelly, Yvette Hernandez and Christine Johnson find a nice open site for the cage; and place Lenny with his lunch in the cage. When other TVs see that Lenny has such great food, they are enticed into the cage. The opening is funnel shaped. The birds go in the large opening, but can’t see the small opening to escape once they are in the cage. Lenny knows that the scientists will be gentle and will release the birds once they have gathered their data, so he doesn’t feel too guilty. Besides, Turkey Vultures lack a syrinx, or vocal organ, so they can’t talk anyway…only hiss and grunt.
The scientists collect lots of statistics on the birds, including blood lead levels. TVs, like Condors, are susceptible to lead poisoning when they ingest spent pellets or bullet fragments in the tissues of animals killed by lead-based ammunition. The data from the two years of sampling will give the scientists a look at lead levels before and after the July 2008 lead ammunition restriction. They hope to see a decrease in the levels and frequency of lead exposure in this year’s samples compared to samples from last spring.
Terra and Yvette captured and sampled 37 TVs last year, and were well on their way to obtaining their goal of almost 40 birds this year when the fog set it. This spring’s fog was thick and high, making it difficult to find a clear site for the cage. The TVs were flying up above the fog and several days went by without any coming down to see Lenny. However, Terra and Yvette were persistent and patient, and ultimately captured and sampled 32 birds; including over 50% of last year’s birds. TVs are ugly and can’t talk, but they have great memories and usually don’t get fooled twice by sweet Lenny.
The data gathered by Terra and Yvette, along with other local scientists, will inform wildlife agencies on the burden and scope of lead exposure in wild birds in California and the effectiveness of lead ammunition regulation in reducing this problem. The information generated from this study will be used for science-based management and will likely play a role in wildlife conservation on both a state and regional level.
And much of this success is thanks to Lenny!
Terry Hallock and Feynner Arias