Short story about a collector alien that relentlessly chases man stuck on an island
I am trying to identify the book or the writer that wrote a story that is an anthology of sci-fi short stories from the 1950s, 1960s or 1970s. The anthology was as a hardback.
An army man is dropped via helicopter on an uninhabited island, for training I believe. Upon exploration, he is discovers all the sizable animals on the island have had something done to them so that they are in suspended animation, not dead but immobilized and not moving. They are arranged in an exhibition like state. 944
He sees upon an alien (I always imagined it as a big Dalek like thing) that makes a straight line for him and he realizes it is responsible for what happened to the animals. The alien is completely impervious to all his attacks and keeps coming at him, I think with a needle out to collect him.
The man panicks and runs off setting traps to crush, stop or block the alien (including a rockfall) but to no avail, he is increasingly panicking and is on the run for 2 to 3 days on the island without sleep trying to stay ahead of the lumbering but relentless alien. We get a cut-shot perspective of the alien which was a robot that an alien race used and released it to collect animal specimen samples of a specific weight range and they left without switching it off. The alien collector has been steadily gaining on the man little by little and finally on the 3rd day, it catches up with the man and just before it attacks, it stops, pauses then it turns and moves on away from him, leaving him alone. The man's helicopter ride comes in and picks him up and the crew is shocked at how bad he looks and they exclaim how it looks like he has dropped 10 pounds of weight in 3 days! He also realizes that the only way to get away from the alien is if you can fly away from the island.
Anyone know which story this is? 1012