Many similar cases might be mentioned, such as the black-throated blue warblers, which are still observed in the mountains of Haiti in the middle of May, when others of this species are en route through North Carolina to breeding territory in New England or have even reached that region. Redstarts and yellow warblers, evidently the more southern breeders, are seen returning southward on the northern coast of South America just about the time that the earliest of those breeding in the North reach Florida on their way to winter quarters. =Nocturnal and diurnal migration= When one recalls that most birds appear to be more or less helpless in the dark, it seems remarkable that many should select the night hours for extended travel. Among those that do, however, are the great hosts of shore birds, rails, flycatchers, orioles, most of the great family of sparrows, the warblers, vireos, and thrushes, and in fact, the majority of small birds. That it is common to find woods and fields on one day almost barren of bird life, and on the following day filled with sparrows, warblers, and thrushes, would indicate the arrival of migrants during the night. Sportsmen sitting in their "blinds" frequently observe the passage of flocks of ducks and geese, but great numbers of these birds also pass through at night, the clarion call of the Canada goose, or the conversational gabbling of a flock of ducks being common night sounds in spring and fall in many parts of the country. The sibilant, nocturnal calls of the upland plover or Bartramian sandpiper and of other shore birds during their spring and fall flights form vivid memories in the minds of many students of migration. Observations made with telescopes focused on the full moon have shown processions of birds, one observer estimating that birds passed his point of observation at the rate of 9,000 an hour, which gives some indication of the numbers of birds that are in the air during some of the nights when migration is at its height. While the steady night-long passage of migratory birds has been recorded, the bulk of the flocks pass during the earlier hours of the evening and toward daylight in the morning, the periods from 8 o'clock to midnight and from 4 to 6 a. m. seeming to be favorite times for nocturnal flight.