APPENDIX. 445 



C. A KEY TO THE EGGS OF MASSACHUSETTS. 



THIS list, limited to the eggs previously described in this volume, 

 is not wholly reliable, since several birds, not yet known to have 

 actually bred in Massachusetts, may do so occasionally, and since 

 eggs vary greatly, often presenting abnormal forms, or forms like 

 those of other kinds. 



I. EGGS UNMARKED. 



A. Color, white. 

 (a.) Laid in holes of trees (or posts and stumps). 



1. > 1.25X1.00. Screech Owl. 26, V. 



(2.) Av. 1.00X.90. Bird entirely brown and white. Acadian Owl. 26, IV, B. 

 3. >1.00X.80,< 1.25X1.00. Bird not red-headed. Pigeon Woodpecker. 25,1. 

 (4.) >1.00X.80,< 1.25X1.00. Bird red-headed. Red-headed Woodpecker. 25,11. 

 (5.) Av. .95X.80. Bird, crown scarlet, upper breast black. Yellow-bellied Woodpecker. 



25, III. 

 (6.) Generally > .80X.65. Bird >9in., (chiefly) black and white. Hairy Woodpecker. 



25, V, A. 

 7. Generally < .80X.65. Bird < 7 in., (chiefly) black and white. Downy Woodpecker. 



25, V, B. 



(8.) Av. .75X.55. Bird metallic green above. White-bellied Swallow* 11, III. 

 (9.) Av. .80X.60. Usually blue. Bird with chestnut breast. Bluebird* 2, I. 



[The Martins and Chimney Swifts no longer (?) build in stumps (etc.), in N. E.] 



(6.) Nests built in trees (or bushes), but not in holes. 



(1.) > 2.75X2.25. White, very impure or dirty. Bald Eagle. 27, VIII. 



2. 2.25 long (or more). Not often pure white. Great Horned Owl. 3 26, VI. 



3. 2.00 long or less ; subspherical. Barred Owl. 26, III, B. 



4. Av. 1.90X1.50. Not spherical. Generally bluish ; often marked. Cooper's Hawk. 

 27, III, B. 



5. Av. 1.60X1.35. Nearly spherical. Long-eared Owl. 26, II, A. 



6. Av. 1.45X1.20. Generally marked. Sharp-shinned Hawk. 27,111, A. 



7. Av. 1.50X1.10. Elliptical. Nest loose and frail. Wild Pigeon. 29, I. 



8. Av. 1.10X.80. Nest loose and frail. Carolina Dove. 29, II. 



9. Av, .75X.55. Often bluish. Nest in bush or shrubbery. Indigo Bird. 15, XX. 

 10. Av. .63X.50. Bluish. Nest in bush or shade-tree. Goldfinch. 15, IV, A. 



(11.) Av. .70X.55. Pure wh. Nest in woods (?). Yellow-bellied Flycatcher* 19, V, C. 



12. Av. .62X.50. Nest in (woods) orchard or shade-tree. Bird olive gray above. Least 

 Pewee. 19, V, B. 



13. (<) .50 long. Hummingbird. 22, 1. 



[The eggs of the Buzzard Hawks and of Traill's Flycatcher may sometimes be white. 

 See II, A, d.] 



1 Many water-birds lay large white eggs, 3 See B, (a), (1). 



some in hollow trees, but these are all tinged * This Flycatcher has not as yet been actu- 



with blue, green, or buff. Some of the Petrels, ally found breeding in Massachusetts. Its 



however, lay a single small pure white egg, eggs, moreover, are not pure white but creamy 



but none do so here. white with distinct and often very conspicu- 



2 The nests of these birds are usually well ous spots of reddish brown. W. B. 

 lined, the Bluebird's generally most warmly ; 



those of the Woodpeckers are rarely so. 



