From Muppet Wiki

Armstrong the Chicken Hawk was a co-host of The Animal Show. During season 1, he mostly hung out with Ollie the Tapir; after the first season, Bunnie Bear became his cohost. The grumpy Armstrong is usually the straight man/victim in these team-ups.

The Armstrong puppet made its first appearance on The Muppet Show episode 502 and he also made an appearance in the Sesame Street song Let's Lay an Egg .