Double‐nesting behaviour and sexual differences in breeding success in wild Red‐legged PartridgesAlectoris rufa

Abstract

Double-nesting behaviour, a rare breeding system in which females lay in two nests, one incubated by herself and the other one by her mate, could be considered an intermediate stage in the evolutionary trend from biparental to uniparental care of single clutches. We examined the occurrence and success of double-nesting behaviour in Red-legged Partridges Alectoris rufa in Central Spain. Clutch size and hatching success were recorded, as well as the variation in these between years and between incubating sexes. Participation in incubation was higher for females (94.76%) than males (41.0%), and the proportion of incubating males varied markedly between years, with no incubating males in one dry year and approximately 50% of males incubating in other years. There was significant variation among years and between sexes in laying date, clutch size and hatching success. Clutch size decreased with later laying date in males and females. The probability of clutch loss to predation differed between sexes, being much higher for nests incubated by females. Our results suggest that both rainfall and predation influence the occurrence and success of double-nesting.

Early exposure to low doses of atrazine affects behavior in juvenile and adult CD1 mice

“…Like in grey partridge, differences in vigilance between sexes are less pronounced during non-breeding seasons (Dahlgren 1990). Moreover, sex dimorphism is less conspicuous in this species than in other Galliforms, and the male can brood and give parental care to chicks, and this could account for rather symmetrical roles in vigilance between sexes (Green 1984;Casas et al 2009). …”

Occurrence of Common QuailCoturnix coturnixeggs in Red‐legged PartridgeAlectoris rufanests

“…On the other hand, because of their smaller size, the Quail eggs might not be properly incubated by Red-legged Partridges (these smaller eggs could end up below the partridge eggs where they would have less contact with the partridge's brood patch). In Red-legged Partridges, both males and females incubate clutches (females often lay clutches in two different nests [Casas et al 2009]), but from our data we cannot say whether clutches incubated by males are more vulnerable to interspecific parasitism than those incubated by females. This would deserve further research, based on a larger sample of nests.…”

“…Each year, we caught and radiotagged adult partridges in February-March to study their breeding biology. A total of 222 Red-legged Partridges were radiotagged during the study (39 in 2003; 44 in 2004; 32 in 2005; 44 in 2007; 38 in 2008; and 25 in 2009 Casas et al [2009] for more details). Each individual was fitted with a necklace radio-transmitter (Biotrack, Dorset, UK, 10 gr.)…”

Are farm-reared red-legged partridge releases increasing hunting pressure on wild breeding partridges in central Spain?

“…Over the three study years, a total of one hundred fifteen partridges were captured in late winter/early spring (Table 1) using cage traps with adult red-legged partridges as a live decoy, which were also baited daily with wheat (Casas et al 2009). Captured birds were ringed, sexed from plumage, biometry and ornaments (Sáenz de Buruaga et al 2001), and a blood sample was taken from the brachial vein (0.5-1 ml).…”

“…For our analyses, we excluded data from 2005, which was characterized by a marked spring drought that considerably reduced red-legged partridge productivity (see Casas et al 2009) and led the hunting managers from estates A, C and D to decide not to hunt that year (Table 1). Three birds were also excluded from analyses because the signal was lost before the end of the hunting season (unknown fate).…”