Depends on the radar, for example radar of AWACS would literally fry people, in case of [Boeing E-3 Sentry][1] it's 1MW (1 million watt), that's why it's not allowed to use it on low altitude and within proximity of other planes. 

Also military radars have tracking mode, which means that rather than having wide beam, it's concentrated in very narrow beam. Theres has been some experimenting in using this to [fry electronic of incoming missiles][2] with short burst of radars power. 

So if you'd point military grade radar in tracking mode at an animal, no doubt you could kill it. However, it's highly unlikely, and I really doubt it could kill animal just by passing by. Normally radars operate in scan mode, which means that beam is scattered.


  [1]: http://www.globalsecurity.org/military/systems/aircraft/e-3.htm
  [2]: http://www.militaryphotos.net/forums/showthread.php?46778-JSF-Raptor-Radar-Can-Fry-Enemy-Sensors