I'm a little thrown off by all the positive reviews. I love birds, and I find crows particularly clever and interesting. After finishing David Attenborough's "Life of Birds" I thought I would move on to this one, for some more focused attention on crows. While it's unfair to compare this to Attenborough's work, it's worth saying that it comes no where near the caliber of quality, footage or insight. I didn't find the documentary to contain any unique or insightful footage, just a regular shot of crows pecking through trash here, and gathering on power lines there. If you've never seen a crow use a tool before to get grubs, then this might be interesting in a couple of places ("Life of Birds" has much better footage of this though).
Now this might be a bit of spoiler, so be warned.
The individuals in this film carrying out a study on the learning cycle of crows did a very poor job, and the evidence was not just inconclusive, but dismissible. The idea was to find out if crows could not only recognize faces but also pass on that information to their young. Those completing the study wanted to see if baby crows would grow up and then still remember the faces of those that their parents found threatening while they grew up. They decided to wear masks and then ,they never explained how, but, while the masks were on they somehow caused the crows to feel threatened or in danger. Then they would walk by the crows without masks and find the crows did not caw but with the masks on they would caw warnings. They radio tagged a very small number of birds to follow as they grew up. They radio tagged them without the masks on. I found this to be a problem in the study. If I were a crow, I would then find those who stole me out of my nest while I was awake, and man handled me to be just as threatening at the individuals in the masks which did... what? Oh yeah, they never even tell you what exactly they did in the masks to upset the birds. Anyway, all but 1 of the crows dies, and when they find the last crow as an adult, they walk past him without the mask, and no response. Then he puts on the mask, and after walking past the crow and walking past it again and staring at it, and not leaving it alone for some time, the crow finally lets out a little caw, that they claim means he remembered and so his parents must have passed down this information to him. I don't think it's impossible for the crow to remember this, but I think they did a terrible job carrying out this study, and it seemed extremely nonscientific. Also the response time of the "warning caw" was very slow, and they have no way of knowing why it cawed. Crows caw, a lot. I get cawed at, and I never dawned a mask and threatened crows. This could have been a much better study... but I guess they did their best... so 3 stars it is.
Overall I found the documentary to be very uninteresting, and the study was annoying. I think crows are smart, I think the study was not.