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THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 124. No. 3. September 20/2 
ties during January-October in 2003 and 2004 to 
help prevent power outages (Tillman el al. 2004). 
Utility company personnel trapped parakeets 
during nest removals by adapting a method 
developed in Argentina (MarteHa et al. 1987). 
Utility crews approached parakeet nest structures 
after dark, covered one or two nest entrances 
using long-handled nets, and then captured birds 
as they flew from the nest (Avery et al. 2006). The 
netted birds were euthanized with carbon dioxide 
as were any nestlings remaining inside the nest. 
All birds from a given nest structure were bagged 
together with a record sheet detailing location and 
characteristics of the nest structure. The number 
of entrances was recorded w hen a nest structure 
was removed, but the number of nest chambers 
within the nest structure was not ascertained. 
Thus, we used the number of entrances as a 
minimum estimate of the number of nest cham¬ 
bers. All contents from a single nest structure 
were comingled during the removal process. 
Thus, w'c could not assign contents to individual 
nest chambers for multi-chamber structures. The 
carcasses were frozen and shipped overnight to 
the Florida Field Station of the USDA’s National 
Wildlife Research Center, Gainesville, Florida for 
necropsy. We tagged each carcass with a unique 
number and stored the necropsied carcasses in 
freezers. Most of the carcasses were discarded in 
2010 when they spoiled following failure of one 
of the freezers. 
We conducted field evaluations of diazaeon, a 
candidate contraceptive for Monk Parakeets in 
electric utility substations in 2006 and 2007 
(Aver) et al. 2008). Utility workers removed 50 
nests during April and May as part of the diazaeon 
study at four substations which served as 
untreated control study sites. There was no effort 
to trap adults, but we documented the contents of 
the 50 nests. 
Body Measurements and Primary Molt.—'We 
measured body mass of each bird on a digital 
scale. We measured wing chord, flattened wing, 
tail length, tarsus, and exposed cut men (from the 
anterior edge of the cere) for adults and fledglings 
(Baldwin et al. 1931), We examined the primary 
feathers of each wing anil scored molt following 
Ginn and Melville (1983): 0 - old; I - missing or 
completely in pm; 2 - just emerging from sheath 
up to 1/3 grown; 3 - new feather 1/3 lo 2/3 grown; 
new feather >2/3 grown with waxy sheath 
remaining; 5 - Ju/ly grown new feather. The 
maximum score for each wing was 50. signifying 
all fully grown, new feathers. We combined the 
molt scores for both wings (maximum score = 
100) and summarized the results by month of 
collection. We distinguished fledglings from older 
birds during June-September by the fresh, unworn 
condition of their recently molted plumage 
(Navarro et al. 1992b). We also noted that 
juveniles had more green on crown and facial 
feathers and less yellow on the breast and belly 
compared to adults at this time of year. 
We dissected each adult and fledgling to 
identify males and females, and we measured 
the diameter of the largest ovum or follicle in 
adult females. We assumed the ova and follicles 
were spherical and converted the linear measure¬ 
ment to volume. Wc also noted the presence or 
absence of an incubation patch (Mammal 1974:. 
We measured the length and width of both testes 
ol adult males. We calculated total testicular 
volume (Mollcr 1991). summarized the results by 
month, and evaluated population level changes 
throughout the year, Few adults were collected in 
September, and we combined that month with 
October in all analyses. We used one-way 
analyses of variance for statistical testing unless 
otherwise stated. 
RESULTS 
Nesting Biology. —Monk Parakeets in south 
Florida are seasonal breeders. Testes volume 
peaked in March-April and steadily decreased 
thereafter (Fig. I A). Females had the same 
temporal pattern as mean size of the largest 
follicle or ovum increased almost a thousand-fold 
Irom February to March and rapidly diminished 
after May (Fig. IB). Nests with eggs occurred 
from 22 March through the first week of July 
(Fig. 2). The nestling period extended from 21 
April to 21 July, except for one nest with two 
nestlings removed in late August. Total contents 
(eggs plus nestlings) of nest structures ranged 
from one to 12. Average (± SE) contents of 
multiple-entry nests on distribution poles (5.6 ± 
0.5; a = 36) exceeded (F, 74 = 5.57; P = 0.0211 
those of single-entry structures (4.4 ± 0.2; n = 
40; Table I). 
We recorded incubation patches for 52 of 66 
(78%) females during April-July. Eight of 104 
(7.7%) females examined in other months had 
incubation patches. Females having incubation 
patches (// = 52, mean ± SE = 117.8 ± 1.1 g) 
during April-July were heavier (P < 0.001: F u w 
= 17.47) than those without (// = 14. mean ± SE 
