270 THE ZOOLOGIST. 



haunts ; and there are indications that they will become still more 

 common. Until the present year I never knew of them nesting on 

 the River Ouse, although, as already stated, they have been known 

 to have nested on its tributary, the River Ivel ; and in 1913 I found 

 them also on the River Lea. In June last I found a pair nesting at 

 Great Barford, and also another pair at Wellington, and I have little 

 doubt they will also be found in other localities along that river. — 

 J. Steele Elliott. 



On the Laying of the Cuckoo (Cuculus canorus). — Two conse- 

 cutive week-ends I spent on the River Ouse and its tributary the 

 Ivel, in Bedfordshire, working upon the distribution of the Reed- 

 Warbler. Finding two of their nests containing eggs of the Cuckoo, 

 without a doubt laid by the same bird, I kept a careful look-out for 

 any additional nests that might also be used by this same Cuckoo. 

 Over sixty nests of Reed- Warblers in all were found on a stretch of 

 six and a half miles of the Ouse, and a few other nests along the 

 River Ivel, within a mile of the junction of the two rivers. The 

 completed clutches of the Reed- Warbler varied from three to five 

 eggs. Of these nests, eight had been selected by a Cuckoo, and five 

 of them contained eggs laid by this one bird, to which the following 

 particulars refer : — 



June 5th. — River Ouse, Blunham. Nest in reed-bed alongside 

 river. Eggs, one Cuckoo with two Reed-Warbler. Incubation about 

 eight days. 



5th. — River Ouse, Blunham. Nest in reed-bed alongside river, 

 fifty yards' distance. Eggs, one Cuckoo with three Reed- Warbler. 

 Incubation about three days. 



12th. — River Ouse, Great Barford. Nest in reed-bed on an island, 

 one mile distant up stream. Eggs, one Cuckoo with one Reed- 

 Warbler. Incubation about seven days. 



11th. — Near River Ivel, Tempsford. Nest in osier-bed and nine 

 feet high, one mile distant east. Eggs one Cuckoo with three Reed- 

 Warbler. Incubation about three days. 



12th. — River Ouse, Blunham. Nest in reeds alongside river, 

 half-mile distant up stream. Eggs, one Cuckoo with three Reed- 

 Warbler. Eggs fresh. 



The distances are taken from the first nest found. The other 

 three nests found containing eggs of the Cuckoo were all at a greater 

 distance away than any in the above area. In stating to what 

 extent each clutch had been incubated, I had not previously con- 

 sidered the space of time that would have elapsed between each 



