Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Nest designs of the artificial nest sites used during the field experiments. Three types of nest sites were used: (A) ‘open’—woodblock drilled lengthwise to form a 4 mm hole, where the hole was not closed; (B) ‘partially closed’—a hole was partially closed on one side with a beech plug; (C) ‘with one side closed’—a hole was fully closed on one side with a beech plug. The cavity volume was approximately 0.9 cm3.
