The various causes of mortality outlined below kill individual birds directly, and … Causes of Bird Mortality Read More » Check out the list of largest living birds in the world. These birds, about the size of the sparrows here in the States, come together in colonies of as many as 500 individuals to build by far the most enormous nests on … First, it should be stated that the single most significant threat to bird populations is habitat destruction, in all of its forms and with all of its causes. Bower birds construct nests on the ground with colorful cloth, trash and whatever else a male can find to attract a mate. Biggest Nest The incubation mounds built by the mallee fowl (Leipoa ocellata) of Australia are up to 15 feet tall and 35 feet wide. Flickr/thinboyfatter This cozy-looking nest belongs to the bushtit. But that does birds an injustice. Sociable weaver’s nests are the biggest nests built by any bird and a single nest can accommodate up to three hundred birds, including their chicks. Eggs will sink, so the birds build floating platform nests out A nest site is estimated to weigh 330 tons. Either way, they are just amazing. Some waterbirds, including many ducks, nest in upland grasslands far from water. Wide 20 foot deep nest was built by a pair of This chart and the following text were prepared in 2003. Spotting a large bird on sky could make you ‘Aww.’ some of the large birds can fly some of them can’t. Any updates would be welcome. Others, such as loons, grebes, coots and gallinules, nest directly on top of the water. The term “bird’s nest” has come to describe a messy hairdo, tangled fishing line and other unspeakably knotty conundrums. A 9 ft. 6 in.