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THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 124. No. 2. June 2012 
2000 lo 2004, a single female laid five 5-egg. fou 
6-egg, and five 7-egg clutches in G19 plus one eacl 
6-egg and 7-egg clutch during 2000 in th< 
neighboring nest box G20 (base area o 
215.3 cm 2 ). Excluding clutches of this female 
reduced the mean value for GI9 from 5.05 eggs, 
nest (n = 44) to 4.60 eggs/nest (n = 30) and result.' 
in a significant correlation, r = 0.728 df = "> ] p < 
0.0001 (Fig. 1). 
Other summaries of individual nesting success 
do not exhibit statistically significant relationships 
with nest-box base area. The relationships be¬ 
tween base area of nest box with hatching success 
(r - 0.353, df = 21, P = 0.099) and with 
surviving brood size (r = 0.357. df = 21, P = 
0.100) have near statistical significance (Fig. 2), 
but these variables themselves are correlated with 
clutch size. No statistically significant relationship 
exists between basal area of nest box and mean 
egg mass (r = 0.094. df = 21. P = 0.45), nor 
between basal area of nest box and mean mass 
ol surviving young at 7 days ot age (r = -0 1 36 
df = 21. P = 0.753). 
There is no indication of any preference for 
particular nest boxes based on nest-box base area. 
There is only a slight positive, but non-significant, 
correlation between base area and date of the nest 
box’s first egg of the season (/• = 0.188, df = 21. 
P - 0.396) and a slight negative, but non¬ 
significant. correlation between base area and 
number ol clutches/ycar (/• = -0.210, df = 2 | 
DISCUSSION 
Clutch size of House Sparrows varies season¬ 
ally with a mid-season high (Murphy 1978. 
Anderson 2006, pers. obs.). The use of multi¬ 
year, whole-season, multi-female data for the 
mean clutch size for each nest box masks several 
factors known to have affects on clutch size. All 
nest boxes at this site were within a circle with a 
6-m radius and pairs, potentially, could select any 
ol the available nest boxes except for constraints 
imposed by behavioral interactions within the 
colony, by which, for example, older, successful 
pairs would likely retain nest sites within and 
between seasons (Anderson 2006). 
I his present study suggests two questions lor 
consideration. (I) Do House Sparrows show any 
preference for size of cavity for a nest site: 
specifically, do they show any preferences for nest 
boxes with regard to base area? (2) Do the physical 
characteristics of a nest box have any impact on the 
breeding success of House Sparrows? 
1 he first question can be addressed best in an 
experimental setting. Mv observations seem to 
show no overt preference for nest boxes with 
regard to size of the base area, but slight trends 
allow speculation of possible biological signifi¬ 
cance. House Sparrows may prefer smaller nest 
boxes since first nesting attempts begin earlier in 
the season for smaller nest boxes and. as one 
consequence, these nest boxes tend also to have 
more nesting attempts. My own subjective 
impressions are that preferred nest boxes at this 
