Wicbnann — A Preliminary Catalog of the Birds of Missouri. 7 



the former is somewhat more severe than that of the latter, the 

 summers being hotter, the winteis colder. It is therefore not 

 suiprising to find slight differences in the summer and win;:er 

 faunas of the two regions, while the migrations occur at nearly 

 the :-same time, owing to the similarit^' in temperatuie of the 

 spring and fall months. 



V. THE CL1MA.TE. 



The climate of Missouri, continental as 't is in a high degree, is 

 one of great variations. Genprally speaking it may be said that 

 it is characterized by hot summers and moderately cold winters, 

 with exceptions of modd'ately hot summers and very cold winters. 

 Maximum temperatures of eighty degrees and over occur during 

 the summer on eighty to ninety days; ninety degrees and over 

 on twenty to thirtv days. In ordinary winters the temperature 

 reaches to and below the freezing point on about (^'ghty days 

 and fah3 below zero on trom ten to twenty days. There are on 

 record a few exceptionally moderate winters like that of 1905-'06 

 when the zero mark was liardiy reached, or reac'iicd only in the 

 more noi'tjiern coimties. There is little difference in the amount 

 and duration of the summer's heat in the different parts of the 

 state, but there is a difference of five degrees in the average 

 winter tem^perature between the northwest and the center, and 

 from ten to fifteen degrees between that of the northwest and 

 the southeast. AH waves, cold and warm, appear first in the 

 northwest and advance southeastward, requiring about twenty- 

 four hours to reach the southeastern corner of the state. The 

 most pronounced polar waves of midwinter are nearly as cold in 

 one i^arfc of the state as in the other, but cold periods are generally 

 of shorter duration in the southeast, mode^'ating more rapidly un- 

 der the more southern sun and the lower elevation. This is espe- 

 cially noticeable in the beginning and at the end of winter, but, due 

 to its northwest-southeast course, the chilling effect of a departing 

 high barometer may still be felt strongly in the southeast when 

 the approaching low barometer has already entered the state "n 

 the northwest with rapidly rising temperature. Such conditions 

 are particularly striking in spring, when north-bound migrants 

 are thereby enabled to depart, while no migration reaches us 

 from the south, then still under the influence of the cold east and 

 southeast wmds of the departed high pressure. The first frosts 

 occur late in October, in the southern part sometimes not befoie 



