168 
The Cuckoo's Egg 
Summary. 
Length in 
millimetres 
Species 
.... 
umber oi 
Mecin 
Standard 
Deviation 
Coefficient 
of 
Significance Test 
(Katio of dmerence to its probable 
Variation 
error) 
Cuculus canorus 
243 

1 "0585 
4-79 
C. canorus- Anthus pratensis 
(Meadow-Pipit-Cuckoo) ... 
45 
yj ofoo 
'i OW 
difference not significant (I'l) 
Anthus pratensis 
74 
19-7 
1-2504 
6-37 
C canorus- Accentor inodularis 
(Hedge-Sparrow-Cuckoo) ... 
14 
231 
1-0116 
4-37 
difference significant (3 71) 
Accentor modularis ... 
26 
20-0 
0-8096 
4-02 
C. canorus-Erithacus rubecula 
^^IvODni-V^UCK.OOj ... ... 
16 
22-5 
0-6628 
2-50 
difference not significant (1-25) 
Erithacus rubecula ... 
57 
20-2 
0-8565 
4-24 
C. canorus-Motacilla, sp. 4 
(Wagtail-Cuckoos) 
26 
22-6 
0-8783 
3-88 
difference not significant (1-25) 
Wagtails estimated ... 
19-9 
C. canorus- Anthus trivialis 
(Tree-Pipit-Cuckoo) 
15 
231 
0-8504 
3-68 
difference significant (4-5) 
Anthus trivialis 
27 
20-0 
0-6978 
3-489 
C. canorus-Troglodytes parvu- 
lus ... 
15 
21-1 
0-7558 
3-58 
difference significant (9-3) 
Troglodytes parvulus 
Estimated 
17-7 
from 
W. J. Gordon 
Breadth in millimetres 
Cuculus canorus 
243 
16-5 
0-6496 
3-93 
C. canorus-Anthus pratensis 
(Meadow-Pipit-Cuckoo) ... 
45 
16-7 
0-3815 
2-28 
difference significant (3-4) 
Anthus pratensis 
74 
14-6 
0-5611 
3-84 
C. canorus- Accentor modularis 
(Hedge-Sparrow-Cuckoo) ... 
14 
16-8 
0-5161 
3-07 
difference significant (2-4) 
Accentor modularis ... 
26 
14-7 
0-4146 
2-81 
C. canorus-Erithacus rubecula 
(Robin-Cuckoo) 
16 
16-4 
0-5326 
3-24 
difference not significant ('96) 
Erithacus rubecula ,. 
57 
15-4 
0-4771 
3-09 
C. canorus-Motacilla, sp. 4 
(Wagtail-Cuckoos) 
26 
16-6 
0-4389 
2-58 
difference not significant (-93) 
Wagtails estimated ... 
14-9 
C. canorus-Anthus trivialis 
(Tree-Pipit-Cuckoo) 
15 
16-6 
0-4397 
2-65 
difference not significant ("75) 
Anthus trivialis 
27 
15-1 
0-4488 
2-97 
C. canorus-Troglodytes parvu- 
lus 
15 
15-8 
0-3042 
1-92 
difference significant (12-3) 
Troglodytes parvulus 
Estimated 
12-7 
from 
W. J. Gordon's 
"Our Country's 
Birds" 
