I can go first.
There are a variety of impacts that affect birds.
There was a publication in Avian Conservation and Ecology, which is the journal that we co-publish here in Canada, looking at human-caused mortality factors of birds. It did document all the biggest mortality factors facing our birds, from a human perspective.
Transmission-line collisions and wind turbines were certainly on there. The most significant, though, are free-roaming cats—outdoor cats kill about 100 million birds per year in Canada—and window collisions. On average, window collisions kill 25 million birds per year in Canada, whether that's through lights being left on when they shouldn't be or bad building code designs that aren't in place for proper window fittings.
The big challenges those reports deal with are climate change and habitat loss, which are another level of threat facing a lot of these birds. The “State of Canada's Birds” report is a distillation of the numbers. It identifies the groups of birds that are most affected. It is then our job to follow up to find the correlating factors for those declines.