There is something un-self-consciously voyeuristic about bird-watching. Peeping at "peeps" with binoculars or a high-powered scope seems like the most natural thing to do for a birder. The epitome of this seemingly benign intrusion into the lives of other species innocently going about their feathered lives is the "bird cam".
The advent of high-speed internet streaming video has enabled researchers and hobbyists alike to observe the nesting behavior of Osprey pairs, the social encounters at Puffin roosts, and the inter-species interaction among visitors at bird feeders, among many other viewing opportunities.
Feeder cams are best viewed during the day. If you go to the Sapsucker Woods Feeder Cam (operated by the Cornell lab) at 6PM PST, the birds will have all gone to bed. Come back in the AM, and there'll be plenty of visitors and even a live audio stream. Nest cams and roost cams, however, potentially offer around-the-clock interest, but only during the proper season like the Live Nest Cams hosted at several locations by the Institute for Wildlife Studies (IWS). The same is true of the Osprey Cam provided by Golden Gate Audubon, which also offers a choice of views of the nest environment.
The Cornell cams are streamed by a YouTube service, which generally works on any device, and there is also a dedicated Cornell Lab Channel, with symbols which show whether the stream is live, and the time at the camera site. The IWS cams and Audubon Bird Cams, in contrast, are carried by Explore, which doesn't work well on all browsers, particularly those which don't use the Flash video player.
Not unexpectedly, there are also compendium sites, with marvelous collections of links for global locations and species. One of the more remarkable is ViewBirds.com, a nest and feeder cam list maintained by Vicki Dziadosz at the University of Pittsburgh and arranged in taxonomic order for the nests, and by geographic location for the feeders. Be sure to check for daylight hours at the target location. Helpfully, cams which display best (if at all) on Windows/Internet Explorer devices are marked as such.
Another comprehensive resource is the MangoLink site, which even breaks bird cams down into "Wild", "Captive", "Feeders in Gardens", and many more categories. Again, many of these cams can only be only viewed on specific device, browser, and video player combinations. In each case, though, there are enough still images to encourage exploration. Want to see a White-tailed Eagle in Estonia?
The extreme example of season-dependent cams is the Gentoo Penguin (a Favorite) installation at O'Higgins Station, Antarctica. In this case, the task is not to determine time zone or a target season, but rather to remember that the South Pole is very dark nearly half the year. But that makes it easy, because if it's between the Fall and Spring equinoxes in the Northern Hemisphere, the lights are probably on for the Gentoo Penguins. So, too, are the many wide-angle and telephoto cams maintained by researcher Martin Grund, with a multingual website that allows access to an astonishing variety of roost locations and time frames. After years of up-close and personal observations, Martin probably recognizes all the penguins by name.