1922. BuRKiTT. — Birds' Song. 121 



Blackbird. — Evidence of pairing began with February, 

 and after the first week of February a good many seemed 

 paired. Whether paired or not territory could be defined 

 by presence and by perching up ; but there was yet no 

 song. Many birds were in territory/ and paired a fortnight 

 before song began anywhere, which this year was not till 

 the fourth week of February. The normal first egg was 

 in first or second week of April. What song there was in 

 all the period before eggs was erratic, occasional, and very 

 feeble and began by a few minutes at roosting time (d.d.e.) 

 with a tendency in any singer after about the middle of 

 March to also have a song earlier in the evening and to 

 last longer. A very occasional bird might be heard in 

 ordinary day time. 



WTiere a male has long delay in being mated the song 

 is more regular, more prominent and longer. For example, 

 I had one which sang for five weeks before there was sign 

 of a mate. 



With regard to the subsequent course of d.d.e. song, all 

 birds seemed to be joining in it after the middle of March, 

 but at the end of March this song w^nt off, with a very 

 rare exception, and never recurred. (This is a curious 

 feature which arises from my notes, if correct. I did not 

 consider it at the time. My last year's notes partly 

 corroborate it). 



As to song at d.d.m. it seemed to begin in first w^eek 

 of March and was not general till after the middle of March, 

 but was not at its height in volume and period this year 

 till the second week in April (incubation was then 

 commencing) ; it then continued regularly and was 

 apparently joined in by all Blackbirds till the end of May, 

 going off as June began and not ending till all song ended. 



Throughout April, day song became freer, but was never 

 voluble till near the middle of May. It then remained, 

 this year (1922), the leading feature in the day's song till 

 it began to go off in the fi.rst week in June. I heard no 

 song at all after June 9th. Apart from general observation 

 in the country I dealt with six nests round me. Four of 

 them had the first egg between April 7th and loth, one on 

 the 2nd, one on the 20th. 



