class="references">179. Life Histories of North American Flycatchers, Larks, Swallows, and Their Allies, May 8, 1942.

191. Life Histories of North American Jays, Crows, and Titmice, January 27, 1947.

195. Life Histories of North American Nuthatches, Wrens, Thrashers, and Their Allies, July 7, 1948.

196. Life Histories of North American Thrushes, Kinglets, and Their Allies, June 28, 1949.

197. Life Histories of North American Wagtails, Shrikes, Vireos, and Their Allies, June 21, 1950.

The paragraphs on distribution for the Colima and Kirtland’s warblers were supplied by Dr. Josselyn Van Tyne with his contributions on these species.

All other data on distribution and migration were contributed by the Fish and Wildlife Service under the supervision of Frederick C. Lincoln.

The same general plan has been followed as explained in previous bulletins, and the same sources of information have been used. It does not seem necessary to explain the plan again here. The nomenclature of the Check-List of North American Birds (1931), with its supplements, of the American Ornithologists’ Union, has been followed. Forms not recognized in this list have not been included.

Many who have contributed material for previous Bulletins have continued to cooperate. Receipts of material from several hundred contributors has been acknowledged in previous Bulletins. In addition to these, our thanks are due to the following new contributors: G. A. Ammann, O. L. Austin, Jr., F. S. Barkalow, Jr., Ralph Beebe, H. E. Bennett, A. J. Berger, Virgilio Biaggi, Jr., C. H. Blake, Don Bleitz, B. J. Blincoe, L. C. Brecher, Jeanne Broley, Maurice Broun, J. H. Buckalew, I. W. Burr, N. K. Carpenter, May T. Cooke, H. L. Crockett, Grace Crowe, Ruby Curry, J. V. Dennis, E. von S. Dingle, M. S. Dunlap, J. J. Elliott, A. H. Fast, Edith K. Frey, J. E. Galley, J. H. Gerard, Lydia Getell, H. B. Goldstein, Alan Gordon, L. I. Grinnell, Horace Groskin, F. G. Gross, G. W. Gullion, E. M. Hall, R. H. Hansman, Katharine C. Harding, H. H. Harrison, J. W. Hopkins, N. L. Huff, Verna R. Johnston, Malcolm Jollie, R. S. Judd, M. B. Land, Louise de K. Lawrence, R. E. Lawrence, G. H. Lowery, J. M. Markle, C. R. Mason, D. L. McKinley, R. J. Middleton, Lyle Miller, A. H. Morgan, R. H. Myers, W. H. Nicholson, F. H. Orcutt, H. L. Orians, R. A. O’Reilly, A. A. Outram, G. H. Parks, K. C. Parkes, M. M. Peet, J. L. Peters, F. A. Pitelka, Mariana Roach, James Rooney, Jr., O. M. Root, G. B. Saunders, James Sawders, Mary C. Shaub, Dorothy E. Snyder, Doris Heustis Speirs, E. A. Stoner, P. B. Street, H. R. Sweet, E. W. Teale, A. B. Williams, G. G. Williams, R. B. Williams, Mrs. T. E. Winford, and A. M. Woodbury.

As the demand for these Bulletins is much greater than the supply, the names of those who have not contributed to the work during recent years will be dropped from the author’s mailing list.

Dr. Winsor M. Tyler has again read and indexed for this volume a large part of the current literature on North American birds and has contributed four complete life histories. Dr. Alfred O. Gross has written stories on the yellow-throats (Geothlypis trichas) and has contributed three other complete life histories. Edward von S. Dingle, Alexander Sprunt, Jr., and Dr. Josselyn Van Tyne have contributed two complete life histories each.

William George F. Harris has increased his valuable contribution to the work by producing the entire paragraphs on eggs, including descriptions of the eggs in their exact colors, assembling and averaging the measurements, and collecting and arranging the egg dates, as they appear under Distribution; the preparation of this last item alone required the handling of over 5,600 records.

Clarence F. Smith has furnished references to food habits of all the species of wood warblers. Aretas A. Saunders has contributed full and accurate descriptions of the songs and call notes of all the species with which he is familiar, based on his extensive musical records. Dr. Alexander F. Skutch has sent us full accounts of all the North American wood warblers that migrate through or spend the winter in Central America, with dates of arrival and departure. James Lee Peters has furnished descriptions of molts and plumages of several species and has copied several original descriptions of subspecies from publications that were not available to the author.

Eggs were measured for this volume by American Museum of Natural History (C. K. Nichols), California Academy of Sciences (R. T. Orr), Colorado Museum of Natural History (F. G. Brandenburg), C. E. Doe, W. E. Griffee, W. C. Hanna, E. N. Harrison, H. L. Heaton, A. D. Henderson, Museum of Comparative Zoology (W. G. F. Harris), and Museum of Vertebrate Zoology (M. Jollie).

The manuscript for this Bulletin was written in 1945; only important information could be added. If the reader fails to find in these pages anything that he knows about the birds, he can only blame himself for failing to send the information to—

The Author.

LIFE HISTORIES OF
NORTH AMERICAN WOOD WARBLERS

Order PASSERIFORMES: Family Parulidae

By Arthur Cleveland Bent
Taunton, Mass.

GENERAL REMARKS ON THE FAMILY PARULIDAE

Contributed by Winsor Marrett Tyler

The family of wood warblers, Parulidae, is the second largest family of North American birds, surpassed only in number of species by the family Fringillidae. The wood warblers occur only in the Western Hemisphere; they are distinct from the Old World warblers, Sylviidae, although the two families play a similar rôle in nature’s economy.

The wood warblers are largely nocturnal migrants, whose long journeys in the dark of night over sea and lake and along the coast expose them to many perils, one being the lighthouses they strike with frequently fatal results. Their notes are seldom heard from the night sky during their spring migration, but on many a calm, quiet night in August and September, as they fly overhead, their sharp, sibilant, staccato notes punctuate the rhythmic beat of the tree-crickets singing in the shrubbery and stand out clearly among the soft, whistled calls of the migrating thrushes.

The length of migration varies greatly; the pine warbler withdraws in winter only a short distance from the southern limit of its breeding range, whereas the most northerly breeding black-polls migrate from Alaska to the Tropics. In spring many species migrate at nearly the same time, apparently advancing northward in intermittent waves of great numbers during favorable nights. Flocks made up of sometimes a dozen species together flash about in their bright plumage during the week or two at the height of the migration and furnish days of great excitement to ornithologists. Their return in late summer and autumn is more leisurely and regular; in loose flocks they drift slowly by for several weeks, their southward passage evident even in daytime. The flocking begins early, soon after nesting is over, and to the north is apparent early in July, if closely watched for, even before the leaves begin to wither. The mixed fall flocks, with adults in winter plumage and young birds in duller colors, present many fascinating problems in identification as the birds move quietly along.

[Author’s Notes: When I asked Dr. Tyler to contribute these remarks we discussed Professor Cooke’s (1904) theory of trans-Gulf migration,