BLUE-GRAY GNATCATCHER. 
POLIOraiA OERULEA. 
Char. Male : above, bluish gray, darker on head, paler on rump ; 
forehead and line over the eye black ; beneath, pale bluish white ; wings 
dusky; tail longer than the body, the outer feathers partly white. Fe- 
male ; similar to the male, but lacking the black on head. Length 4% 
to 5 inches. 
Nest. A graceful, cup-shaped structure, saddled on limb of a tree 15 
or 20 feet from the ground; composed of felted plant fibre ornamented 
externally with lichens and lined with feathers. 
E);gs. 3-5; bluish white, speckled with bright brown; 0.55 X 0.45. 
But for the length of the tail, this would rank among the 
most diminutive of birds. It is a very dexterous, lively insect- 
hunter, and keeps commonly in the tops of tall trees ; its 
motions are rapid and incessant, appearing always in quest of 
its prey, darting from bough to bough with hanging wings and 
elevated tail, uttering only at times a feeble song of tsee tsce tsee, 
scarcely louder than the squeak of a mouse. It arrives in the 
State of Pennsylvania from the South about the middle of April, 
and seldom passes to the north of the States of New York and 
Ohio, though others, following the course of the large riv'ers, pen- 
etrate into Kentucky, Indiana, and Arkansas. Its first visits 
are paid to the blooming willows along the borders of water- 
courses, and besides other small insects it now preys on the 
troublesome mosquitoes. About the beginning of May it forms 
its nest, which is usually fixed among twigs, at the height of 10, 
or sometimes even 50, feet from the ground, near the summit 
