qT=2&tQ=The ___________ inflates a huge, red sac on its throat during mating season?&tC=puffin|robin|frigate bird|pelican&cC=3&fB=The male frigate bird has a stretchy red sac on his throat that can swell into a very large red balloon when he wishes to attract a mate.<br><br>Unable to swim, walk with ease, or take off from a flat surface, the frigate bird is most comfortable in the air. It has the largest wingspan to body weight ratio of any bird in the world, and is able to stay in the air for more than a week at a time!