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THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 3. September 2011 
Nest age (days) 
hina" in 2008 ttemS survivaI rates ^ DSR ) f° r eac h nest age of Grey-backed Thrushes in Dagang Forestry Farm, 
Nest-site Characteristics. —Nests were built in 
15 plant species, including eight tree and seven 
shrub species. Forty of the 79 nests (51.9%) were 
in shrubs, 32 (40.5%) were in trees, and six 
(7.6%) were on stumps remaining after logging 
events (average height of stumps was 1.27 ± 
0.49 m). Among nests in shrubs, 17.7 and 16.5% 
were in Manchurian Schneider buckthorn and 
Chinese hawthorn, respectively. The predominant 
trees used for nesting included Japanese elm 
(1 1.4%), Ussurian pear ( Pyrus ussuriensis) 
(10.1%), and Dahurian birch (10.1%). Mongolian 
Scotch pine (Pinus sylvestris L. var. mongolica 
Litvin) was the only evergreen tree used. 
Sixty-nine of 79 (87.3%) nest trees had DBH 
equal to or >3.0 cm. Tree species with DBH 2 
3.0 cm and their relative abundance at nest sites 
(5,442 trees) and random plots (4.520 trees), 
respectively, was calculated and total density of 
trees at nest sites (1,722/ha) was higher than in 
random plots (1.430/ha). Species composition and 
their reladve abundances were similar between 
nest sites and random plots (Fig. 2). Grey-backed 
1 brushes preferred Manchurian Schneider buck¬ 
thorn. Chinese hawthorn, Manchurian lilac, Amur 
honeysuckle, Japanese elm, Manchurian pear, and 
Dahurian birch as nesting trees, and did not select 
bird cherry ( Padus racemosa), Mandshurian 
linden (777/Vi mandshurica), large leaf Chinese 
ash, Mongolian oak, and Amur cork-tree (Phello- 
denitron amurense), which accounted for 33.6% 
of the total trees (Fig. 2). 
selected variables were built by Program MARK 
and ranked by AIC c and W h All statistical 
analyses were performed with STATISTICA 
Version 8.0 (StatSoft Inc. 2007); values are 
presented as means ± SE. 
RESULTS 
Seventy-nine nests of Grey-backed Thrush 
were found in the plots. Fifteen of the 79 nests 
were excluded from DSR analysis because of 
predation (cracked egg shells in the nests and/or 
on the ground) (12 nests), abandoned after 
extended incubation (2 nests), and destroyed 
during a storm (1 nest). All 79 nests were 
included in analyses of nest-site selection, but 
only 64 nests were included in estimation of DSR. 
Overall DSR, irrespective of the variation 
among nests and all dates, was 0.9563 ± 0.0072 
Samp,e size based on exposure days = 
/bU). The apparent nesting success based on the 
overall constant DSR was 0.274 (0 9563 21 ') DSR 
of Grey-backed Thrushes decreased during the 88- 
day nesung season, according to the trend model; 
rr ~ 1/(1 + ex P (-3.2049040 + 0.0042267*/)) 
(where / refers to the day in the nesting season). 
„ of each nest age was estimated, and 
averaged DSR of laying (0.9581 ± 0.0009) and 
hteJT mB u m5 *° ± °- 0027 > were 
. h£ ! n lhOSC ol mcubation (0.9561 ± 0.0021) 
and brooding (0.9558 ± 0.0021) periods (Fig n 
diffcre " ces were detected 
een nestling periods (F = 1.955, P = 0.147). 
