dotterel or dottrel /dotˈ(ə-)rəl/

1. A kind of plover, named from its apparent stupidity in allowing itself to be approached and caught
2. A stupid fellow, a dupe

• at the best of times
• at the bottom of
• at the coalface
• at the crack of dawn
• at the double
• at the drop of a hat
• at the earliest
• at the eleventh hour
• at the end of one's tether
• at the end of the day
• at the expense of
• at the feet of
• at the first blush
• at the fore
• at the full
• at the hand of
• at the hands of
• at the head of the poll
• at the heels of
• at the instance of
• at the latest
• at the least
• at the mercy of
• at the most
• at the outside