6 
Nebraska Bird Review 
clutches hatched over a 48-hour span, 
indicating that the females began in¬ 
cubating on day two of egg laying 
in four-egg clutches and day three 
of laying in five-egg clutches. 
b. Mean growth and growth rates 
in weight and other body parts. 
Figure 1 illustrates the growth in 
weight and body parts of all 
the Goldfinch nestlings. Growth in 
weight and other body measurements 
are plotted on a semi-logarithmic 
basis; if growth was logarithmic 
over the entire nestling period the 
growth curves should be a straight 
line. Since they are not (total length 
showing the closest approximation) 
straight lines, the growth rate (R) 
was calculated by the method used 
by Banks (1959) when growth is 
non-logarithmic. This is: 
R = 2.3 (log - log W^) 
(2.3 being a factor to convert 
logarithms to the base 10 to natural 
logarithms). 
This figure is valid for compari¬ 
sons only if one assumes that growth 
during any one day is logarithmic 
even though over the entire nestling 
period it is not. In this formula, 
is the weight (or other measure¬ 
ment) at T^, and is the weight 
(or other measurement) at a later 
time, T^. 
Tables 1 and 2 show the mean 
growth in weight and other body 
parts and Table 3 shows the growth 
rate. There is rapid growth in the 
first few days, and then a decline 
in rate of growth similar to that 
shown by Banks (1959.) for the 
White-crowned Sparrow (Zonotrichia 
leucophrys) Dawson and Evans 
(1957, 1960) for the Field Sparrow 
(Spizella pusilla), Chipping Sparrow 
(Spizella passerina) and Vesper 
Sparrow (Pooecetes gramineus). 
TABLE 1 
MEAN GROV/TH OF GOLDFINCH NESTLINGS 
. Mean^ 
Day 
N 
Mean^ 
Weight 
Range^ 
N 
Wing 
Length 
0 
165 
1.2 
0.7-1.7 
22 
5.5±0.1 
1 
158 
1.9 
0.9-2.7 
20 
6.0+0.1 
2 
165 
2.7 
1.5-3.7 
19 
7.5±0.2 
3 
154 
3.7 
1.5-4.9 
16 
9.5+0.2 
4 
142 
4.6+0.1 
1.6-62 
9 
12.0+0.3 
5 
131 
5.8+0.1 
1.5-7.8 
4 
16.5 
6 
129 
7.0+0.1 
1.8-8.8 
4 
20.0 
7 
129 
8.2+0.1 
5.7-10.0 
4 
24.5 
8 
124 
9.3+0.1 
6.4-11.7 
4 
28.5 
9 
123 
9.9±0.1 
6.2-12.2 
3 
30.5 
10 
110 
10.4+0.1 
8.0-13.6 
2 
34.5 
11 
89 
10.7+0.1 
5.7-13.2 
- 
- 
12 
58 
ll.liO.l 
7.0-13.4 
- 
- 
13 
30 
11.6+0.2 
9.4-14.0 
- 
- 
14 
12 
12.2 
9.1-14.0 
- 
- 
15 
3 
11.8 
11.5-12.2 
- 
- 
1 Nearest O.I grams 
2 All the birds representing the min¬ 
imum values for wei^t eventually 
died of starvation except those on 
days 10, 12, 13, 14, and 15. 
3 Nearest 0.5 mm 
Maher (1964) for the Snow Bunt¬ 
ing (Plectrophenax ni/valis) and 
Lapland Longspur (Calcarius lap- 
ponicus), and Holcomb and Twiest 
(unpub., b) for the Redwing. The 
only obvious differences between 
these species are that Goldfinches 
and Snow Buntings remain in the 
nest longer. The Goldfinches continue 
to grow until they obtain a higher 
percentage of adult size before leav¬ 
ing the nest (Holcomb, 1968). 
Table 3 shows an index for each 
measurement. This is the mean of 
the R values over the entire nestling 
