Friday, August 24, 2007

Post-Apocalyptic Pigeons: Bird Life near an LA Farm Field

On a recent trip to California I stopped by the Smokin' BBQ, an ocean-side food stand more notable for its resident bird population than its pulled pork sandwiches. The birds looked post-apocalyptic, dusty with missing feathers and several readily-apparent maladies. Post-apocalyptic standouts included a pigeon with a broken wing and only one functional foot (one foot was oversized and useless) and a pigeon with at least 5 protuberant tumors growing from its head.

I am no biologist, but I am also not blind. With 100% of my observed pigeon population looking so bedraggled, I am guessing that some environmental factor must be to blame. My educated, but uninformed guesses include: 1) pesticide exposure from surrounding farm fields, 2) traffic fumes or 3) the Smokin' BBQ.

In particular, I wondered if pesticides could be to blame. While all of Los Angeles has horrible traffic, birds in every area do not look so miserable. This made me suspect some exposure from farm fields surrounding the Smokin' BBQ, in addition to traffic exhaust. I did a little bit of research into birds and their usefulness as environmental indicators, just to see if there was anything to my theory. It turns out that birds provide good indicator species for environmental health and scientists often use birds to monitor heavy metal bioaccumulation. Michael Hulse et al., Environmentally Acquired Lead, Cadmium, and Manganese in the Cattle Egret and Laughing Gull, 9 Arch. Environm. Toxicol. 65 (1980). Studies using feral pigeons have shown the birds are useful bioindicators of atmospheric exposure and traffic exhaust because of their biological and ecological characteristics, including, limited mobility, high metabolism, rapid breathing and ingestion of urban debris. Dong-Ha Nam, et al., Montiroing for Pb and Cd Pollution Using Feral Pigeons in Rural, Urban and Industrial Environments of Korea, 357 Science of the Total Environment 288 (2006).

Scientists have found that pigeons from urban areas are just as contaminated with heavy metals as pigeons from industrial zones, though less contaminated than rural pigeons. Id. I found it interesting that pigeons from urban areas are just as contaminated with lead as are pigeons from industrialized areas, despite conversion to lead-free gasoloine. Id.

All of this metal accumulation does take a toll on the pigeon, as the birds of the Smokin' BBQ aptly demonstrated (at least that's what I think). Lead, in particular damages the DNA in liver and kidneys, meaning that it has high carcinogenic potential. Pauline Schilderman, et al., Possible Relevance of Pigeons as an Indicator Species for Monitoring Air Pollution, 105 Environmental Health Perspectives 322 (1997). Other toxic effects include feather fraying, flying and reproductive problems and death. Katsuhisa Honda, Distribution of Heavy Metals . . . In Korea, 15 Arch. Envirnm. Tox. 185 (1986). Glad I'm not a pigeon.

This last phrase makes me question how far I really am from a pigeon. After all, I have a liver, kidneys and lungs that could be affected by heavy metals. My only advantages are body size, slower breathing, limited pesticide exposure(I hope) and a diet that does not include asphault. A little too close for comfort I think.

Scientists have focused their attention on pigeons as an indicator of air quality and have firmly established that breathing nasty air and eating urban debris are definite no no's. I'm more curious about whether pigeons that ingest or inhale pesticides show similar levels of heavy metal accumulations. I think they must. After all, farm chemicals also contain toxic organochlorine compounds and heavy metals. I'm guessing that the pigeons at the Smokin' BBQ not only breath traffic fumes but also inhale or ingest pesticides from nearby farmfields, which would explain why they look so much worse than pigeons from Pasadena.

I reported my pigeons to some bird people in California who are checking them out (if they didn't think I was a fruitcake). I'll provide updates if anything comes of it and a picture of the pigeons per Morgan's request(if I can persuade my friend Wendy to take one).