Bird Species

Climate change is not only driving the extinction [blank] many bird species, but it may also mean that the birds that survive will have less diverse physical features. In the last 50 years, the US and Canada have lost [blank] than one-quarter of their birds - an estimated 3 billion animals - due to human activity. A study released last year found that [blank] are now 600 million fewer birds in Europe than there were in 1980. Extinctions are expected to continue according to the latest State of the World's Birds report, which found that 48 percent of birds worldwide [blank] known or suspected to be undergoing population declines. "We know we're going to lose species, but we don't know much about other aspects of diversity that are also super important," says Emma Hughes at the University [blank] Sheffield in the UK. As extinctions of some of the rarest and most distinctive birds continue, Hughes wanted [blank] know if surviving species will become more alike over time - a process called "homogenization".