Delaware from the west. The last two places to report arrivals were situated farther up the river and some distance back from it. All this confirms the general idea that in migrating most, if not all, of the various land birds follow river valleys and invade the upland districts, lying back from either side, by way of the smaller tributaries.
| 1885. | 1886. | 1887. | 1888. | 1889. | 1890. | 1831. | 1892. | |
| Flicker | April 10 | Mar. 24 | Mar. 26 | Mar. 30 | Mar. 28 | Mar. 26 | Mar. 30 | April 2 |
| Chimney swift | April 22 | April 23 | April 22 | April 20 | April 15 | April 22 | April 16 | April 27 |
| Hummingbird | April 29 | May 12 | May 12 | May 14 | May 7 | May 11 | ||
| Kingbird | May 6 | May 11 | May 7 | May 6 | May 6 | May 14 | May 1 | May 4 |
| Crested flycatcher | May 2 | May 12 | May 3 | May 1 | May 8 | May 1 | April 30 | May 3 |
| Pewee | April 3 | Mar. 20 | Mar. 21 | Mar. 22 | Mar. 27 | Mar. 27 | Mar. 31 | April 3 |
| Wood pewee | May 6 | May 15 | April 30 | May 13 | May 12 | May 14 | May 6 | May 17 |
| Red-winged black-bird | Mar. 4 | Feb. 19 | Feb. 19 | Feb. 21 | Mar. 13 | Mar. 12 | Feb. 25 | Mar. 9 |
| Meadow lark | Feb. 10 | Mar. 19 | Mar. 21 | Mar. 14 | Mar. 12 | Feb. 23 | Mar. 17 | |
| Baltimore oriole | May 5 | May 4 | May 2 | May 2 | May 7 | May 1 | May 1 | May 3 |
| Purple grackle | Mar. 16 | Mar. 7 | Feb. 19 | Feb. 21 | Mar. 2 | Feb. 13 | Feb. 18 | Mar. 6 |
| Chipping sparrow | April 8 | April 9 | April 8 | Mar. 31 | Mar. 29 | April 8 | April 13 | April 4 |
| Field sparrow | April 11 | April 7 | April 9 | April 2 | Mar. 29 | Mar. 13 | Mar. 15 | Mar. 26 |
| Chewink | April 22 | April 23 | April 27 | April 18 | April 11 | May 1 | April 18 | April 24 |
| Indigo bird | May 16 | May 11 | May 7 | May 12 | May 12 | May 10 | May 8 | May 10 |
| Scarlet tanager | May 9 | May 12 | May 5 | May 8 | May 9 | May 4 | April 28 | May 3 |
| Barn swallow | April 22 | April 19 | April 21 | April 12 | April 22 | April 19 | April 19 | April 24 |
| Red-eyed vireo | May 7 | May 11 | May 4 | April 29 | May 5 | April 30 | May 2 | May 3 |
| Black-and-white warbler | April 30 | May 4 | April 27 | April 21 | April 20 | April 30 | April 24 | May 1 |
| Yellow warbler | May 6 | May 4 | May 2 | May 5 | May 11 | May 1 | May 8 | May 4 |
| Myrtle warbler | May 2 | April 10 | May 2 | April 25 | April 20 | April 27 | April 18 | April 7 |
| Black-throated green warbler | May 2 | May 11 | May 5 | April 26 | May 5 | May 2 | April 19 | April 30 |
| Ovenbird | April 30 | May 3 | April 29 | April 30 | May 3 | May 3 | April 29 | April 30 |
| Maryland yellow throat | April 29 | April 24 | April 28 | April 30 | May 6 | April 30 | May 1 | May 3 |
| Chat | May 2 | May 12 | May 5 | May 5 | May 11 | May 5 | May 10 | May 3 |
| Redstart | May 2 | May 4 | May 3 | May 1 | May 4 | May 3 | April 29 | April 30 |
| Catbird | May 2 | May 4 | May 3 | May 5 | May 5 | May 5 | May 4 | April 30 |
| Brown thrasher | April 24 | April 25 | April 28 | April 15 | April 22 | April 30 | April 19 | April 30 |
| House wren | May 3 | April 27 | April 24 | April 28 | April 14 | April 30 | April 19 | May 5 |
| Wood thrush | May 2 | May 1 | May 1 | May 1 | May 3 | April 30 | April 23 | May 2 |
| Veery | May 11 | April 25 | May 3 | May 6 | May 2 | April 28 | May 4 | |
| Hermit thrush | April 13 | April 7 | April 9 | April 3 | April 10 | April 13 | April 12 | April 3 |
| Robin | Mar. 7 | Mar. 10 | Feb. 28 | Feb. 19 | Mar. 7 | Feb. 26 | Feb. 24 | Mar. 9 |
| Bluebird | Mar. 18 | Feb. 17 | Feb. 21 | Mar. 8 | Feb. 23 | Feb. 17 | Mar. 9 |
The fact of greatest importance resulting from these observations was that relating to temperature. It was found that there was always a marked increase in the number of individuals of a given species following a warm wave of temperature as marked by a decided rise of the thermometer. The following graphic representation, based on the abundance from day to day of three common and easily observed species—the brown thrasher, chipping sparrow, and flicker—affords an interesting illustration of the relative movements of the two waves. It will be understood that the numbers in the extreme left-hand column refer to the relative abundance of individuals of the three
