Artist Beatriz da Costa, left, and Cina Hazegh release pigeons outfitted with sensing devices from the top of the clock tower at the San Jose Museum of Art in downtown San Jose, Calif., Tuesday, Aug. 8, 2006. Pigeons with backpacks and cell phones will be taking to the sky and sending air quality data to a blog as part of a whimsical project that blends science, art and activism. Researchers at the University of California, Irvine hope the project will fill in gaps in knowledge about the air we breath, and spark debate on the topic. (AP Photos/San Jose Mercury News, Susanna Frohman) ** MAGS OUT, NO SALES **