carpenter] the nesting OF THE BLACK TERN 



173 



or an old muskrat house furnishes the foundation. On this the 

 bird arranges a shallow "saucer" of grass, and deposits the three 



Upper — The Black Tern incubating. 

 Lower — Nest of Tern on old muskrat house. 



eggs. The eggs vary in color considerably, from greenish to 

 quite dark brown and are "thickly spotted and blotched lilac 

 and darker brown." The dark markings are often gathered 



