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1

The effect of environmental factors and nesting conditions on clutch overlap in the Feral Pigeon Columba livia f.urbana [Gm.]

100%
Hetmanski T., Wolk E.
Polish Journal of Ecology
|
2005
|
tom 53
|
nr 4
Clutch overlap is a reproductive strategy of the Feral Pigeon, which results in an increase in the number of clutches produced by a pair and, as follows, an increase in the number of young raised. It is dependent on the length of time the clutch is cared for and the length of the interval between clutches. Both these component elements of clutch overlap are directly affected by environmental conditions, such as the length of day and ambient temperature. The duration of clutch care and the clutch interval were distinctly shorter in the warmer part of the year with a longer day than during the fall and winter. We believe that ambient temperature has a significant effect on the length of the clutch interval, as it is a decisive factor in the achievement of thermoregulation ability in the nestlings. Earlier achievement of this ability by nestlings in higher ambient temperatures (at Ta = 21.5°C, normothermy appeared in the 6th to 7th post-embryonic day in the life of nestlings, while at Ta = 19.5 °C – in 8–9 days) allows both parents to forage for longer periods of time and to start a new breeding cycle earlier. We confirmed that nesting conditions (the number of nests in a breeding pair's territory, brood size and location of the nest in the colony) also influenced the duration of clutch care and the length of clutch interval, and therefore, the degree of clutch overlap. The clutch interval was shorter when parents only cared for one young, than when two young were in the nest. Breeding pairs with large territories that included two nests had shorter clutch intervals than those pairs with only one nest. Young raised in nests located close to egresses left the colony more quickly than young in nests farther away
2

Dispersion asymmetry within a Feral Pigeon Columba livia population

84%
Hetmanski T.
Acta Ornithologica
|
2007
|
tom 42
|
nr 1
23-31
3

Plumage polymorphism and breeding parameters of various Feral Pigeon [Columbia livia Gm.] morphs in urban area [Gdansk, North Poland]

84%
Hetmanski T., Jarosiewicz A.
Polish Journal of Ecology
|
2008
|
tom 56
|
nr 4
683-691
In 2007, the population of Feral Pigeons in Gdańsk City (almost 500,000 inhabitants) constituted 14 200 individuals. The population density in the built-up areas of Gdańsk (82.2 km²) was estimated at an average of 17.2 birds 10⁻¹ ha, however the highest density occurred in Gdańsk’s city centre area (5.7 km²) – 44 birds 10⁻¹ ha. Blue plumage type pigeons dominated in the population (93%), while black, red and albinotic types were rarely observed. Melanistic birds were more frequently found than blue-bar birds, whose plumage is inherited from the Rock Pigeon. However, blue-bars were more numerous in Gdańsk compared with other pigeon populations in central and northern Europe. Old pre-war buildings were not confirmed as influencing the plumage pattern of pigeons. Melanistic birds were more numerous in old district of Oliwa, whereas blue bars in old Gdańsk city centre. The plumage of pigeons in small flocks of up to 50 birds did not differ from that of pigeons in flocks of over 50 and 100 birds. Blue-bars, checkers and dark checkers did not differ in body mass or breeding parameters. Other causes of polymorphism variation among pigeons in a population are discussed.
4

Timing of breeding in the Feral Pigeon Columba livia f. domestica in Slupsk (NW Poland)

84%
Hetmanski T.
Acta Ornithologica
|
2004
|
tom 39
|
nr 2
The study was conducted from 1997-2001 in the city of Słupsk. Observations of individually marked birds were conducted from blinds located at city-centre sites where Feral Pigeons breed. The pigeons bred throughout the year, with peak broods in spring and summer. Different pairs timed their breeding such that the beginning of the season (from October to September of the next calendar year) overlapped the dates of completion (from April to December). 10% of pairs had already begun breeding in the autumn, while 86% did so between January and May. The remaining pairs (young ones, in particular) started breeding even later, mainly because of the lack of suitable nesting sites. The breeding period most often ended between August and October (75% of pairs), when the pigeons began their moult. 91% of the young birds joined the breeding population in their second calendar year of life. The remaining young birds had their first broods in the first or third calendar year of life. Pairs of young birds started nesting 2-3 months later than adult birds. The average length of a pair's breeding season was 183 days.
5

Breeding parameters and recruitment in Feral Pigeons Columba livia f. domestica

84%
Hetmanski T., Barkowska M.
Acta Ornithologica
|
2008
|
tom 43
|
nr 2
159-166
This research was conducted on the Feral Pigeon population in Słupsk (NW Poland). Breeding parameters and the number of parental pairs' young recruited into the breeding population were determined for 52-112 marked pairs over three breeding seasons. Pairs had an average of 4.4 broods and produced 3.6 fledglings per breeding season. From 39 to 49% of pairs in various seasons did not have any young recruited. Every fourth pair (25-30%) had a single young bird recruited, from 12 to 20% of pairs — two young, from 4 to 11% — 3 young, and 6% of pairs had from four to six young recruited. The number of recruits depended on the breeding parameters of the parents: it was lowest among young pairs (low quality birds), those that began breeding late in the season, had a short breeding season, or low breeding success. In contrast, high quality birds with a long breeding season, the highest reproductive parameters and breeding success, had the most young recruited. Survival rate of young after leaving the nest was not found to be influenced by the starting date or the length of the breeding season of pairs. However, nesting conditions, such as pair density in colonies, may influence the fate of young birds after they leave the nest and are recruited.
6

The development of bird communities in new housing estates in Warsaw

84%
Luniak M.
Memorabilia Zoologica
|
1994
|
tom 49
7

The timing of fledging and annual post-fledging survival of juvenile feral pigeons, Columba livia, in a city area [Pomerania, NW Poland]

67%
Hetmanski T.
Polish Journal of Ecology
|
2007
|
tom 55
|
nr 2
Research on the annual postfledging survival of young Feral Pigeons Columba livia was conducted in 1998-2001 in five breeding colonies located in the city centre of Słupsk (NW Poland, area 43 km²). Breeding pairs and their offspring were individually ringed. A total of 1016 clutches were studied, as was the fate of 809 fledglings. It was found that although fledglings were produced throughout the entire year, about 81-93% of young was leaving the nest in the period between April and September. The peak period of fledging occurred in May, August or June accordingly in successive study years. The dynamic of fledging in one year reflected the pairs’ egg laying activity occurring two months earlier. Juvenile mortality was highest during the first month after fledging and was found to be 45% of young birds. The main cause of death was hunger, as the young, inexperienced individuals were unable to compete successfully with adults for food at foraging areas. Loss of young clearly decreased with every successive month. The annual survival rate of juveniles produced in a calendar year was 30%. Almost all the juveniles surviving their first year of life joined the breeding population. Young produced in winter and spring had better survival rates than did those leaving the nest in summer, and especially, in autumn. The differences in survival rates found among the seasons of the year most likely resulted from changes in the pressure of competition for food in foraging areas.
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