Roof window security. What sensor to use?

Question

Sensors

There is a task of alerting a person to a certain area on the roof of a house, by type: a person walks on the roof and only when approaching the dormer window and / or cornice the sensor is triggered. What is the best sensor to use? It is necessary that it does not work on birds and cats, at the same time it snows on the roof in winter.
Anyone with experience on how to do this please let me know.

Answer 1

It is better to use both the camera and the GSM module, so that when motion is detected, an SMS is sent or dialed. Immediately connect to the camera and see if it's a false positive or an intrusion.