bird-nesting

• birds'-nesting
• bird nesting

bird-nesting (uncountable)

1. (UK, Australia) The, formerly common, hobby of looking for birds' nests, often with the intention of collecting the eggs.
   • 1934, Henry G. Lamond, An Aviary On The Plains, page 189:

     Let's go bird-nesting.

   • 1939, George Orwell, Coming Up for Air, London: Victor Gollancz, page 56 (Penguin 1962 edition):

     They [the boys] all had catapults […]. In summer they used to go fishing and bird-nesting.

2. (US) A custody arrangement in which the child of divorced parents remains in one home while the parents take turns to move in and out.
   • 2007, Gayle Rosenwald Smith, What Every Woman Should Know about Divorce and Custody:

     An unusual, but not unheard of, setup called bird nesting is when children stay in the house and the parents take turns moving in and out.

   • 2017, Etta Faire, Feliz Navi-Dead: A Sketchy Matchmaker Mystery:

     He should feel lucky I agreed to test out this bird-nesting custody arrangement this month. It was a huge inconvenience for me to have the kids staying full time in the house while Mark and I traded time living there.