66 



ORNITHOLOGIST 



[Vol. 10-No. 5 



and rain, while areas of high pressure are cloud- 

 less, we would naturally suppose that migration 

 would take place during high pressure, but as has 

 already been said, the area of low pressure at- 

 tracts a south wind and the increased warmth 

 more than overbalances the cloudiness. Of all 

 the migration of last Spring, it seems probable 

 that fully sixty per cent took place in cloudy 

 weather. It is also probable, though I am not 

 aware that it has as yet been proved, that in F(M 

 migration, these conditions are reversed and the 

 larger part takes place in clear weather. 



For the purpose of putting the notes on record 

 that others may compare them with their own 

 observations, we will give the full record for the 

 seven days from March 19th to 35th, 1884, though 

 we are aware that it will be uninteresting and 

 tedious to the general reader, who can stop at 

 this point. 



March 18th, 1884, at 11 p. m., there was no 

 marked atmospheric disturbance .throughout the 

 United States, the minimum of the cold wave 

 had occurred the day before, and the tempera- 

 ture was gradually rising in the Upper Mississippi 

 Valky. It is this part of the Mississippi Valley, 

 from 39° northward, to which we shall confine 

 our study. The temperature was quite high (oO°) 

 at St. Louis, 37 at St. Paul, but fell rapidly 

 from there northwest to 20° at Moorhead. (It 

 need hardly be said that no one can follow the 

 rest of this article .satisfactorily, without a map 

 before them.) The barometer varied only two- 

 tenths of an inch, from 29.9 inches in eastern 

 Arkansas and southern Illinois, to 30.1 at Moor- 

 head. Prevailing winds, very light E. to N., 

 cloudy, with several light rains. There was little 

 change toward the morning of March 19th. ex- 

 cept the shifting of the wind to N., and N.W., 

 while Ihe area of low pressure moved east to 

 Cape Hatteras. Very little migration took jilace, 

 the few birds which did move belonging exclu- 

 sively to those which we have marked in a former 

 article, "the birds of the first wave," that is. 

 Ducks, Geese, Blackbirds, Meadow Larks, 

 Robins and Bluebirds. It is these birds with 

 which we have to deal in our study of these 

 seven days. Migration is reported from southern 

 Wisconsin and northern Illinois, against a north- 

 east wind with the temperature but two or three 

 degrees above freezing, and from east central 

 Kansas, under slightly warmer conditions. It 

 would seem likelj' that some of these notes belong 

 to a warm wave which occurred two daj's before, 

 but it is also certain that some Ducks and Geese 

 were migrating in the early morning hours 

 straight against the northerly winds. 



At 11 p. m.. of the lOtli, an area of slightly 



lower pressure had just passed over the Upper 

 Mississippi Valley and the barometer rose steadi- 

 ly all night. Between St. Paul and St. Louis the 

 temperature remained the same as the daj' before; 

 northward it was slightly higher. Winds light, 

 and everywhere from N. E. , N. W. , and W. Tem- 

 perature from 45 at St. Louis, to 26° at Moorhead. 

 Average barometer at 11 p. m., 30.07, at 7 a. m,, 

 of the 20th, 3 J. 15. Cloudy everywhere except in 

 the Lake Superior region. In general, verj' un- 

 favorable to migration, yet new arrivals are still 

 noted from the same places as on the day previous, 

 with the addition of records from southeastern 

 Dakota, eastern Nebraska and south central Iowa. 

 It would seem that the Ducks and Geese were so 

 desirous of reaching their breeding grounds that 

 they pushed northward, in spite of the wind and 

 the clouds, as soon as the temperature rose two or 

 three degrees above freezing, regardless of the 

 fact that the Winter's snow still covered the 

 ground, the lakes and rivers, still bound with icy 

 chains. Not until a week later did any streams 

 open in the region which was now being invaded 

 by the mi.gratory hosts. 



March 21st is marked by very high barometer 

 and quite a marked advance of the isotherm of 

 30° to points north of Duluth and Moorhead. 

 There was no place in the Upper Mississippi Val- 

 ley at 11 p. m., March 20th, where the pressure 

 was less than 30.3, and in western Dakota it was 

 30.3. Calm weather, or very light N. winds 

 prevailed, with clear weather along the Mississip- 

 pi and the great lakes, and cloudy weather with 

 light rains on the Missouri. Minimum tempera- 

 ture at St. Louis 43°, at LaCrosse 37°, St. Paid 

 30°, Moorhead 23°. A moderately fair night for 

 migration. It is the culmination of the high 

 pressure, and already in the .southern Rocky 

 Mountain region is developing the low pressure 

 which is to bring about the immense movements 

 of the next three days; already the isotherms in 

 that quarter are beginning to move northward, 

 and the wind along the gulf coast has changed to 

 S.E. The birds .seem to have a foreknowledge 

 of the approaching change and there are double 

 as many "firsts" recorded as two days before. 

 Some of these come from central Missouri, where 

 the change is already slightly felt. Otherwise 

 they are from the same districts as the day previ- 

 ous. There is practically no advance of the van, 

 but a filling up of the country already traversed 

 by the scouts. 



The night of March 21st, at 11 o'clock, an area 

 of low barometer, 29.9 inches, was passing east- 

 ward across the Upper Mississippi Valley and 

 was central at North Platte, Neb. It produced 

 S.E., winds of moderate strength in all the 



