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Ítem A ‘slow pace of life’ in Australian old-endemic passerine birds is not accompanied by low basal metabolic rates(Springer Verlag, 2016-05-01) Buttemer, William A.Life history theory suggests that species experiencing high extrinsic mortality rates allocate more resources toward reproduction relative to self-maintenance and reach maturity earlier (‘fast pace of life’) than those having greater life expectancy and reproducing at a lower rate (‘slow pace of life’). Among birds, many studies have shown that tropical species have a slower pace of life than temperate-breeding species. The pace of life has been hypothesized to affect metabolism and, as predicted, tropical birds have lower basal metabolic rates (BMR) than temperate-breeding birds. However, many temperate-breeding Australian passerines belong to lineages that evolved in Australia and share ‘slow’ life-history traits that are typical of tropical birds. We obtained BMR from 30 of these ‘old-endemics’ and ten sympatric species of more recently arrived passerine lineages (derived from Afro-Asian origins or introduced by Europeans) with ‘faster’ life histories. The BMR of ‘slow’ temperate-breeding old-endemics was indistinguishable from that of new-arrivals and was not lower than the BMR of ‘fast’ temperate-breeding non-Australian passerines. Old-endemics had substantially smaller clutches and longer maximal life spans in the wild than new arrivals, but neither clutch size nor maximum life span was correlated with BMR. Our results suggest that low BMR in tropical birds is not functionally linked to their ‘slow pace of life’ and instead may be a consequence of differences in annual thermal conditions experienced by tropical versus temperate species. © 2016, Springer-Verlag Berlin Heidelberg.Ítem Breeding biology and egg temperatures of Black-faced Brush-finches (Atlapetes melanolaemus), Neotropical montane songbirds(Blackwell Publishing Inc., 2016-01-01) Londoño Guerrero, Gustavo AdolfoBlack-faced Brush-finches (Atlapetes melanolaemus) are a common species restricted to the Andes of southern Peru and western Bolivia. We provide the first description of the breeding biology of this Neotropical montane passerine, including an analysis of incubation behavior and egg temperatures. We found 47 nests during seven breeding seasons (2007–2013) near Manu National Park, Peru. Nesting occurred in late July, peaked in early October, and continued into early December. All clutches consisted of two eggs, and the mean incubation period (14.8 ± 0.2 d) was relatively short compared with related species. Nest attentiveness increased and the length of foraging trips decreased as the incubation period progressed, but the number of foraging trips/day was constant. Egg temperatures when birds returned to incubate were negatively correlated with the duration of incubation bouts, whereas ambient temperature and the duration of the previous incubation bout were positively correlated with the duration of foraging bouts. Eggs were consistently incubated at lower temperatures (24-h mean = 32.1°C) than other Neotropical and temperate species. When incubating birds left nests, egg temperature dropped below the physiological zero temperature (24–27°C) in ~11 min. Nestlings had a high growth rate (k = 0.60) and a long nestling period (mean = 13.8 d) compared with related Neotropical and temperate emberizines. By showing that the duration of incubation and foraging bouts are affected by different intrinsic and extrinsic factors, we provide evidence that incubation is not only temporally dynamic, but also finely modifiable. Our results also suggest that embryos of high-elevation Neotropical songbirds are particularly resistant to ambient temperature extremes and low incubation temperatures, emphasizing the need for more studies of egg thermoregulation and its consequences for development, growth, and survival. We conclude that closely related species, both on different continents and at the same locations, may differ in parental care strategies and development regimes, cautioning against broad generalizations regarding species groups or geographic areas. © 2016 Association of Field OrnithologistsÍtem Brood parasitism by the enigmatic and rare Pavonine Cuckoo in Amazonian Peru(American Ornithological Society, 2017-04-01) Sánchez Martínez, Manuel A.Brood parasitism is an uncommon and understudied strategy in Amazonian bird communities, within which only 5 species are known to be brood parasites. We present data on the brood-parasitic behavior of the Pavonine Cuckoo (Dromococcyx pavoninus) in 3 host species of small-bodied flycatchers in the Peruvian Amazon that construct hanging globular nests with side entrances. During the 7 yr of the study, we encountered 74 nests of these 3 hosts, but parasitism occurred only in 9 nests (12.2%) in 2 yr. Only 1 Pavonine Cuckoo egg was deposited in each host nest (n = 7), and eggs were markedly dissimilar in size and coloration between hosts and parasite. Incubation investment per day was slightly higher (4%) for 1 parasitized nest than for nonparasitized nests. Overall, 33% of parasitic eggs (n = 6) hatched; cuckoo nestlings apparently removed host eggs and killed host nestlings. The nestling period lasted 24 days, and the growth-rate constant based on nestling mass (k = 0.23) was slower for parasite nestlings than for their hosts (k = 0.27 and 0.31). Food provisioning rates were greater in 1 parasitized nest (2.1 ± 0.7 feedings hr-1 nestling-1) than in nonparasitized nests (1.1 ± 0.4). Nestling cuckoos may further mimic the plumage of their host nestlings. Our results suggest that Pavonine Cuckoos negatively affect their hosts' breeding success and are engaged in a coevolutionary arms race with hosts that have defenses against parasitism. © 2017 American Ornithologists' Union.Ítem Nesting behavior of male and female Undulated Antshrikes (Frederickena unduliger)(Association of Field Ornithologists, 2016-03-01) Londoño Guerrero, Gustavo AdolfoUndulated Antshrikes (Frederickena unduliger) inhabit dense lowland humid forest understory and, as with other species of antbirds, many aspects of their behavior and ecology are poorly known, especially their breeding biology. We provide the first detailed information about their breeding biology based on three nests monitored in the buffer zone of the Manu National Park, Madre de Dios, Peru, from August to December in 2012 and 2013. Nests (N = 3) were large cups woven to the crossing of two horizontal branches. Eggs were white with purplish hairlines and spots, and all three clutches consisted of two eggs. Both males and females incubated eggs and fed nestlings, but only females incubated eggs at night.Ítem Nesting biology of the Lanceolated Monklet (Micromonacha lanceolata) in southeastern Peru(Wilson Ornithological SOC, 2016-09-01) Londoño Guerrero, Gustavo AdolfoThe Lanceolated Monklet (Micromonacha lanceolata) is a puffbird (Bucconidae) generally considered rare throughout its range. This species is little-studied and its reproductive behavior is largely unknown. Here, we provide the first detailed account of its nesting biology. All 17 nests consisted of round tunnels in earthen banks terminating in widened brood chambers. Tunnels averaged 405.41 +/- 59.52 mm in length (n = 14) and 68.64 +/- 13.12 by 57.89 +/- 12.20 mm (n = 16) in diameter at the entrances. The clutch size was two. The unmarked, white eggs averaged 22.53 +/- 1.04 by 18.29 +/- 0.71 mm (n = 22) and weighed 3.84 +/- 0.39 g (n = 19). The incubation period, determined from one nest was 25 days. The number of trips made from three nests averaged 3.42 +/- 1.12 per day (n = 33), with each absence lasting an average of 70.54 +/- 89.98 mins (n = 113). Nest attentiveness steadily increased from 11.55 to 71.73% and on-bouts from these three nests averaged 166.28 +/- 96.58 mins (n = 79). During the nestling period, which we determined from one nest to span 22-23 days, food deliveries consisted of large insects and larvae; averaged over four nests, attendants made 1.72 +/- 0.78 (n = 28 days) deliveries per hour.