POTTERS H (2009) Breeding biology of a smal nest box nesting population of Stock Dove Columba oenas in Noord-Brabant. LIMOSA 82 (1): 1-12.
Breeding phenology and breeding success were studied
in a small population of Stock Doves breeding in nestboxes
in the southern Netherlands. The study area was a
2.8 ha mixture of small meadows, woodlots and tree
rows amidst agricultural fields and grassland. From 1986
nest boxes suitable for breeding Stock Doves were
mounted and in 1992-2000 25-27 such nest boxes were
permanently available. The boxes were checked from
mid March through mid September at 14-days interval.
Data were gathered about nest building, attendance of
adults, number and freshness of eggs and number and
age of nestlings.
Since Stock Doves may produce several clutches or
broods in the same or different nest boxes, the number
of pairs depends on the way it is calculated (Fig. 1). The
decrease in the number of pairs in 1994 can be fully explained
by an increasing number of Jackdaws Corvus
monedula (Tab 1) which bred in the same boxes and
were dominant over the doves. After the eggs of the
Jackdaws were systematically taken, Jackdaw numbers
gradually declined and Stock Doves recovered even to
above their previous numbers.
First onset of breedingwas 28 February, butmost pairs
started laying in May, July and August. Last date on
which chicks were seen in a nestbox was 27 October. A
small dip in occupancy of nest boxes in the end of June
indicates synchronised breeding that fades in the course
of the season (Figs 2 and 3). Deviations from this pattern
in some yearsweremainly caused byweather conditions
(cold springs and long lasting wet spells) and competition
for the boxes with other species. Some pairs produced
overlapping broods (young of the current and
eggs of the next brood at the samemoment) in the same
nest box. Probably overlapping broods were also produced
in separated nest boxes, but this was hard to
prove since birds were not marked. The phenomenon
occurredmost frequently in yearswhen nest box occupancy
and competitionwith Jackdawswas highest (Fig. 3).
During 1988-2000, 52% of 1536 eggs hatched and
44%fledged (Tab 2). In the field I had the impression that
low hatching rate was mainly caused by intraspecific
competition, but annual hatching success did not correlate
with population size. Especially in March many
clutches were lost due to nest box competition with
Jackdaws.
Nearly all clutches contained two eggs, but five times
three eggs were found. It is not sure if these clutches
were produced by one female, since egg dumping is not
a rare phenomenon in Stock Doves.Mean brood sizewas
1.77 (110x1, 339x2, 5x3) young and 1.73 young fledged
per successful breeding attempt (107x1, 284x2, 1x3).
Over the years the number of fledglings per successful
breeding attempt was remarkably stable, but the
amount of successful broods was not (Tab 3). Chickmortality
occurred mostly (60 cases) in their first week of life
and less often in their second week (20) or at later ages
(16). Probably, most young died because of bad weather
with continuous rain. Taken into account the considerable
number of pluckings of juvenile Stock Doves in and
near the study area, a second peak in mortality occurred
just after fledging.
The maximum number of eggs found in a nest box in
one season amounted 4 times 15-16, 7 times 13-14 and
17 times 11-12. Probably these eggs were produced by
more than one female. On the other hand the numbers
presented in Table 4 probably underestimate the reproduction
per pair, since pairsmay well have occupied several
nest boxes. Nevertheless reproductive success was
surprisingly similar to that found in surrounding countries
(Tab 5).Stock Dove Columba oenas
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