This was something that experts thought it had to happen for the simple reason that they knew migratory birds fly for days without stopping but it has now been documented by the study below. What I found incredibly interesting is that they can actually sleep with both brain hemispheres at the same time as well as ‘make do’ with one single hour of sleep!!! Birds can sleep with ‘one eye open’ by shutting down one brain hemisphere but keeping the other one in a state of semi-alertness so they can hear a predator approaching (this is what the ‘night watch’ birds do -the ones that position themselves on the periphery of the flock so as to ‘guard’ them) so I always thought that this was what they did when they slept in flight during migration but now they found that they can actually sleep with both! Amazing, isn’t it?! The whole article is full of interesting details (like that, when the frigate birds are in deep sleep -REM- they drop their head in flight but the flight pattern remained identical - WOW) so I highly recommend it, guys!https://www.sciencedaily.com/releases/2 … 111738.htm
They really have to do it that way to keep from being left behind. The center birds can sleep and just stay in the flock. I read somewhere that the lead bird changes every few minutes since that is the most strenuous position. They have the arrangement that the lead bird goes to the back and the one behind him takes point.
Well, yeah, unless there is a crying child in the row behind them.