I’ve been meaning to read this since it first came out, and at one point I even had an ARC of it, I think for the UK release. I ended up grabbing it and the sequel on our way to the airport, and read it on the flight. Which was possibly not a good idea given all the plane crashes at the start, heh. I don’t quite buy the explanation given in the book for that — genetically manipulated birds all somehow released at once and in multiple places worldwide? Seems a bit of a hole in the story there.
Still, if you elide the science stuff (e.g. I’m also not sure introducing alien DNA via mitochondrial DNA would have reliable effects), this is still pretty fun. It’s definitely YA, with the preoccupations of teenage readers fairly front and centre. What stands out is less the plot and more the characters. Even then, it’s not characterisation I’m talking about, but character diversity. The main character is, for instance, actually bisexual! And she actually initially read to me as ace, maybe grey-A, because she doesn’t seem to grok attraction as a general thing.
So that’s pretty cool. I’m not overwhelmed by plot and character, though there are some great moments — Reese’s mother, for example, and her adult life going on in the background — but it’s enjoyable and easy to read.