Nebraska Bird Review 
3 
GROWTH AND CALCULATION OF AGE 
IN THE AMERICAN GOLDFINCH 
LARRY C. 
INTRODUCTION 
Walkinshaw (1939) reported on 
the breeding biology of the Ameri¬ 
can Goldfinch (Spinus tristis). He 
weighed and measured several nest¬ 
lings each day and reported mean 
daily growth. The present objective 
was to expand upon his study and 
record some of the finer details of 
mean growth and relative growth 
rate. 
Holcomb and Twiest (unpub. b) 
reported on mean growth, rate of 
growth, and calculation of age for 
the Red-winged Blackbird {Age- 
laius phoeniceus) nestlings. It was 
desired to make a comparison of 
growth of Goldfinch nestlings with 
that of Redwings, and also to dis¬ 
cover if the characteristics used to 
calculate age in Redwings would be 
of value for Goldfinches. 
METHODS AND PROCEDURES 
Goldfinch nestlings were studied in 
1963, 1964 and 1965 at Toledo, Ohio. 
The population was located within 
the city limits in an area where 
second-growth vegetation, hedge - 
rows, and weed fields prevailed. A 
description of nest sites, nest build¬ 
ing, egg laying and incubation in this 
area may be found in another pa¬ 
per (Holcomb, unpub.) 
Nests were visited at least once 
each day and the weights and mea¬ 
surements were obtained at nearly 
the same time each day. Nestlings 
were marked in the sequence of 
hatching by placing fingernail polish 
on toenails (toenail 1, nestling one, 
HOLCOMB 
etc,). If more than four nestlings 
were present, the other foot was used 
to mark toenails indicating nestling 
five and six. New polish was usually 
required every two days. Weights 
were obtained to the nearest one- 
tenth gram on a double-beam bal¬ 
ance after the nestling had been 
handled sufficiently to cause void¬ 
ing of wastes. 
A record was kept of the frequency 
with which wastes were voided at 
the time the nestlings were handled 
at the nest, to determine if they 
gained control over the '‘comfort 
movement” as they grew older. 
Daily records were kept on the 
nestlings as to whether the eyes were 
closed (0), cracking open (1), half¬ 
open (2), or fully open (4), as they 
developed. 
Weights of nestlings were record¬ 
ed all three years. The remaining 
observations and measurements were 
made in 1964 and 1965. 
Measurements of growth were 
made on the following parts of nest¬ 
lings : 
toe span - distance from the tip of 
toe one to tip of toe three when ex¬ 
tended - nearest mm 
total length - distance from the an¬ 
terior tip of the culmen to the tip 
of the tail (including retrices when 
present) - nearest mm 
tarsus - nearest one-half mm 
wing - distance from the last bend in 
the wing (radiale region) to the 
tip of phalanges (before feathers 
were present) and to the tip of 
primary eight after it emerged 
any but Canadas in the flock until 
this bird was recovered. The bird 
apparently is a juvenile, since 
Kortright’s The Ducks, Geese and 
Swans of North America says of 
them “white of head speckled with 
dark feathers”. On this side of the 
Atlantic the Barnacle Goose breeds 
in eastern Greenland. It winters in 
Europe. There are casual records 
from northern and eastern Canada, 
and (all fall records) from Massa¬ 
chusetts, New York, Vermont, Ohio, 
and North Carolina. 
