It can take around 8 seconds for the cuckoo to lay her egg. She won’t “buzz “ overhead, but sometimes flies over the moor looking for reactions from the pipits, the idea is to get in and out unseen, although with meadow pipits, that’s a different story as up to 4-5 will attack her as she tries to lay. She’ll watch the host from a hidden vantage point then with a long glide, will land near the nest, find it and lay, or sometimes she will just locate it and check for its suitability as to whether it’s ready for her egg. They’re just starting to lay in pipits nests now ??