SHORT COMMUNICATIONS 
163 
TABLE I. Breeding 
Eurasian Blue Tits using 
de Monsanto (n = 26). 
parameters (mean ± SD) of 
nest boxes in Parque Florestal 
Clutch size 
6.0 ± 1.6 
Eggs hatched 
4.6 ± 2.3 
Chicks fledged 
3.0 ± 12.0 
Hatching rate, % 
71.9 ± 31.3 
Nest survival rate, % 
64.0 ± 36.1 
Breeding success, % 
47.9 ± 30.9 
ground and oriented south or east to avoid the 
dominant moderate-strong winds from north and 
west (e.g.. Lambrechts et al. 2010). Nest boxes 
were equally spaced from each other in a grid 
arrangement of 25 X 25 m (1 nest box/25 X 
25 nr). Nest boxes could not be placed at a few 
points due to site constraints (lack of trees, ponds, 
etc.). 
Eurasian Blue Til Breeding Performance— 
Fifty nest boxes were randomly selected in each 
stand in the 2009 breeding season. We searched 
for reproductive events of cavity nesting birds and 
monitored the breeding performance of Eurasian 
Blue Tits. All occupied nest boxes were checked 
weekly from I March to 3 July to ascertain: (I) 
clutch size, (2) hatching rate (percent of eggs 
incubated to term that hatched), (3) nest survival 
mie (percent of fledglings per number of hatched 
eggs), and (4) breeding success (percent of 
fledglings per clutch). All nests were removed at 
the end <if the breeding season, individually scaled 
itt plastic bags, and analyzed in the laboratory. 
Aromatic Plants Available in Study Area 
and Nests.— Wc considered aromatic plants to 
Be all those with an obvious odor. i.e.. those rich 
m volatile compounds (Clark and Mason 1985, 
(winner 1997). The presence of these plants was 
assessed by conducting line transects along the 
F-W line of the nest box grids. Plants visible on 
each side of the transect line were recorded in 140 
consecutive sample units of 50 X 50 m. Aromatic 
plant fragments in the nests were identified 
through morphological features or scent. 
Statistical Analyses.—Wc used Wilson's 95% 
Confidence Interval (Cl) (following Newcombe 
1998) to compare use of aromatic plant species in 
nests with their availability in the study area. 
Similarly to Dykstra et al. (2009). we considered 
that an aromatic species was used more or less 
than expected if the proportion of sample units 
containing that species was respectively below or 
above the 95% Cl for the proportion of nests 
using that same aromatic species. We used yy with 
contingency tables to test the null hypothesis (H„) 
that nest survival rate is independent of the 
presence of aromatic plants in the nest. 
RESULTS 
We found 26 (34.2%) Eurasian Blue Tit nests 
in 76 nest boxes with confirmed breeding attempts 
of cavity nesting species (Table 1). 
Aromatic Plants in the Study Area and Nests — 
Twelve aromatic plant species were detected on 
line transects; (wo others were recorded only in 
nest contents (Table 2). Another 10 aromatic plants 
were identified in the study area ( Achillea 
operation. Eucalyptus camaldidensis. Juniperus 
oxyccdrus. Lavandula pedanculata. Myrtus com¬ 
munis. Phagnalnn saxatite, Pinus halepensis, P. 
pinea. Ruta clialepensis. Thymus sp.). All taxa are 
autochthonous from the Mediterranean Region 
except for Eucalyptus camaldidensis. Fragments 
from aromatic plants in nests represented a small 
part of the nest material and were placed in the nest 
cup between other materials (BAP. pers. obs.). We 
recorded fragments from one herbaceous and seven 
aromatic shrubby species in 16 ot the 26 analyzed 
nests. The average ± SE number of aromatic plant 
species per nest was 0.96 ± 0.39. 
Use vs. Availahility. —Wilson’s 95% Cl assess¬ 
ment indicated that Dittrichia viscosa. Lavandula 
dentata. and Calamintha haetica were the most 
frequent aromatic plants identilied in nest material 
and were used by Eurasian Blue 1 its more than 
expected according to availability in the study 
area (Table 2). Some aromatic fragments recorded 
in nests were from plant species not detected on 
transects (Lavandula dentata and Mentha spp.). 
Aromatic Plants and Nest Survival Rate of 
Eurasian Blue Tits.—We detected predation of 
nestlings in five nests and excluded them from 
this analysis. We grouped survival rates (SR) from 
the 21 remaining nests into three classes: SR < 
50%. 50% ^ SR < 75%, and SR a 75%, and 
tested the null hypothesis that nest survival rate 
was independent ol the presence ot aromatic 
plants in the nest. Use of yy with contingency 
tables did not allow us to reject H (1 ('/’ = 2.87. 
df = 1. critical value = 3.84, y = 0.05). 
DISCUSSION 
Aromatic species in Eurasian Blue Tit nests 
were a small proportion of all scented plants in the 
study area, suggesting non-random use of those 
species (e.g.. Petit et al. 2002, Mennerat et al. 
