For those few bird species that are exclusively frugivorous, the low protein content of fruits is... more For those few bird species that are exclusively frugivorous, the low protein content of fruits is likely a major nutritional constraint. Physiological mechanisms that allow strict frugivory remain enigmatic, but reduced protein requirements may suffice. We investigated protein requirements of Pesquet's Parrot (Psittrichas fulgidus), a highly specialized, obligate frugivore. Three isocaloric, fruit-based diets of varying protein content (6.1, 3.3, and 2.6% dry mass crude protein) were used in feeding trials lasting three to five days per diet. A minimum dietary protein requirement of 3.2% dry mass was estimated from balance trials. Endogenous nitrogen losses were 0.05 gN kg Ϫ0.75 day Ϫ1 and nitrogen equilibrium occurred at 0.32 gN kg Ϫ0.75 day Ϫ1. Those values are extremely low compared to those of granivorous and omnivorous bird species, but higher than those of nectarivorous species. In terms of nitrogen losses and requirements, Pesquet's Parrot most closely parallels the highly frugivorous Cedar Waxwing (Bombycilla cedrorum). Thus, reduced protein requirements appear to play an important physiological role in ability of highly frugivorous birds to subsist on fruit diets.
Mousebirds (Coliiformes) are unusual in having an exclusively vegetarian diet that includes subst... more Mousebirds (Coliiformes) are unusual in having an exclusively vegetarian diet that includes substantial foliage and by using huddling and sunning to assist thermoregulation. Although previous studies have identified plant species and plant parts consumed by mousebirds, the relative importance of different food types in the diet of wild birds has not been investigated. Furthermore, there is limited information on the extent and importance of their sunning behaviour in the field. We investigated the diet and time-activity budget of White-backed Mousebirds Colius colius at a coastal site in Western Cape province, South Africa. Their diet consisted mostly of leaves (56% of items) and fruits (39%), but diet composition varied with time. Leaves had significantly higher protein content than fruits. White-backed Mousebirds spent most of their time (96%) in stationary activities, particularly sunning (60%), and allocated little time to feeding (4%). However, the proportion of time spent on different activities varied with weather conditions and ambient temperature. When sunning, birds oriented their ventral parts towards the sun 93% of the time, suggesting that exogenous heating may be important for digestion.
Reverse mounting, females mounting males, is a widespread but uncommonly reported behaviour among... more Reverse mounting, females mounting males, is a widespread but uncommonly reported behaviour among birds. Although its function is not fully understood, it is generally accepted that reverse mounting is an integral part of courtship during pair bonding and mating. It has been reported in species of at least 10 orders, but only among three species of columbids previously. Here, I report a casual observation of reverse mounting by two individuals of Spot-winged Pigeons Patagioenas maculosa in the vicinity of the city of Córdaba, Argentina. Components of the display observed in the copulatory sequence of the pair, are frequent in the repertoire of displays during mating and courtship of columbids; yet, reverse mounting is seldom described. These observations support and extend the occurrence of reverse mounting in pigeons.
Global-scope scientific journals have played an important role in upholding a colonial legacy of ... more Global-scope scientific journals have played an important role in upholding a colonial legacy of north-south inequities in ornithology, and they now have a key role to play in increasing equity in scientific publishing. We explore common barriers faced by ornithologists in the Neotropics (Latin America and the Caribbean) and suggest priority actions that Ornithological Applications, Ornithology, and other global-scope ornithological journals can take to increase equity in publication and research uptake. Among the most important problems, we identified (1) restrictive (and north-biased) criteria for assessing research “importance” and “novelty,” (2) the high publication costs of the Author Pay (Gold) Open Access model, (3) language hegemony, (4) under-representation of ornithologists from the Neotropics on editorial boards and as lead authors on invited articles, and (5) lack of attention to ethics of collaboration and citation. We recommend that Ornithological Applications, Ornitho...
A major barrier to advancing ornithology is the systemic exclusion of professionals from the Glob... more A major barrier to advancing ornithology is the systemic exclusion of professionals from the Global South. A recent special dossier, Advances in Neotropical Ornithology, and a shortfalls analysis therein, unintentionally followed a long-standing pattern of highlighting individuals, knowledge, and views from the Global North, while largely omitting the perspectives of people based within the Neotropics. Here, we review problems with assessing the state of Neotropical ornithology through a northern lens, including discovery narratives, incomplete (and biased) understanding of history and advances, and the promotion of agendas that, while currently popular in the north, may not fit the needs and realities of Neotropical research. We argue that future advances in Neotropical ornithology will critically depend on identifying and addressing the systemic barriers that hold back ornithologists who live and work in the Neotropics: unreliable and limited funding, exclusion from international ...
... Open Access Subscription Access. Font Size: Small Medium Large. Short Note Opportunistic bloo... more ... Open Access Subscription Access. Font Size: Small Medium Large. Short Note Opportunistic blood-drinking by Black Crake Amaurornis flavirostris. Carlos Bosque. Abstract. No Abstract. Ostrich 2009, 80(1): 65. Full Text: PDF Ostrich: Journal of African Ornithology. ...
Background: Steatornis caripensis (the oilbird) is a very unusual bird. It supposedly never sees ... more Background: Steatornis caripensis (the oilbird) is a very unusual bird. It supposedly never sees daylight, roosting in huge aggregations in caves during the day and bringing back fruit to the cave at night. As a consequence a large number of the seeds from the fruit they feed upon germinate in the cave and spoil. Methodology/Principal Findings: Here we use newly developed GPS/acceleration loggers with remote UHF readout to show that several assumptions about the behaviour of Steatornis caripensis need to be revised. On average, they spend only every 3rd day in a cave, individuals spent most days sitting quietly in trees in the rainforest where they regurgitate seeds. Conclusions/Significance: This provides new data on the extent of seed dispersal and the movement ecology of Steatornis caripensis. It suggests that Steatornis caripensis is perhaps the most important long-distance seed disperser in Neotropical forests. We also show that colony-living comes with high activity costs to i...
Background: Steatornis caripensis (the oilbird) is a very unusual bird. It supposedly never sees ... more Background: Steatornis caripensis (the oilbird) is a very unusual bird. It supposedly never sees daylight, roosting in huge aggregations in caves during the day and bringing back fruit to the cave at night. As a consequence a large number of the seeds from the fruit they feed upon germinate in the cave and spoil. Methodology/Principal Findings: Here we use newly developed GPS/acceleration loggers with remote UHF readout to show that several assumptions about the behaviour of Steatornis caripensis need to be revised. On average, they spend only every 3rd day in a cave, individuals spent most days sitting quietly in trees in the rainforest where they regurgitate seeds. Conclusions/Significance: This provides new data on the extent of seed dispersal and the movement ecology of Steatornis caripensis. It suggests that Steatornis caripensis is perhaps the most important long-distance seed disperser in Neotropical forests. We also show that colony-living comes with high activity costs to i...
∙ In non‐migratory birds the annual cycle is composed of two critical events, breeding and molt,... more ∙ In non‐migratory birds the annual cycle is composed of two critical events, breeding and molt, spaced by quiescent periods. Breeding in arid environments is frequently dependent on rainfall, but arid environments have unpredictable and irregular precipitation; therefore, birds of arid environments are thought to maintain their reproductive system in a partially or fully activated state to responding rapidly to favorable conditions. Molt most commonly follows the end of reproduction. We studied the annual cycle of the Common Ground‐dove ( Columbina passerina ) for 15 months in arid scrub of Venezuela by determining gonadal sizes and maturation state, and by scoring wing, tail and body molt. As expected, both sexes underwent a brief period of gonadal regression of only about one month during the dry season, and maintained a partly or fully active reproductive system during the rest of the year. Breeding of Common Ground‐doves was associated to rainfall, but not exclusively so; test...
The Disassortative Pollen Flow Hypothesis proposed by Darwin postulates that the relative positio... more The Disassortative Pollen Flow Hypothesis proposed by Darwin postulates that the relative position of anthers and stigmas in distylous flowers enhances pollen flow between flowers of different morphs (legitimate pollination), in comparison to flow between flowers of the same morph (illegitimate pollination). In order to test this hypothesis, we measured pollen transport, mediated by a trained Copper-rumped Hummingbird (Amazilia tobaci), between flowers of the distylous Palicourea fendleri under laboratory conditions. In individual tests, we offered to the hummingbird a pollen donor flower and two emasculated recipient flowers in a controlled sequence. After each foraging bout, we counted the number of pollen grains transported from the donor flower to the stigmas of both recipient flowers. In agreement with Darwin's hypothesis, we found that hummingbirds transport pollen of "pin" flowers in significantly higher numbers to legitimate "thrum" stigmas, even if p...
Post-breeding migration of Oilbirds. -There are few indications in the literature suggesting that... more Post-breeding migration of Oilbirds. -There are few indications in the literature suggesting that Oilbirds (Steatornis caripensis) perform a post-reproductive migration, leaving their breeding caves at the end of the breeding season. Indirect evidence comes from the obser-vations ...
Causes of interspecific variation in growth rates within and among geographic regions remain poor... more Causes of interspecific variation in growth rates within and among geographic regions remain poorly understood. Passerine birds represent an intriguing case because differing theories yield the possibility of an antagonistic interaction between nest predation risk and food delivery rates on evolution of growth rates. We test this possibility among 64 Passerine species studied on three continents, including tropical and north and south temperate latitudes. Growth rates increased strongly with nestling predation rates within, but not between, sites. The importance of nest predation was further emphasized by revealing hidden allometric scaling effects. Nestling predation risk also was associated with reduced total feeding rates and per-nestling feeding rates within each site. Consequently, faster growth rates were associated with decreased per-nestling food delivery rates across species, both within and among regions. These relationships suggest that Passerines can evolve growth strategies in response to predation risk whereby food resources are not the primary limit on growth rate differences among species. In contrast, reaction norms of growth
All in-text references underlined in blue are linked to publications on ResearchGate, letting you... more All in-text references underlined in blue are linked to publications on ResearchGate, letting you access and read them immediately.
Selection of a suitable nesting site may deter-mine failure or success of the breeding attempt. F... more Selection of a suitable nesting site may deter-mine failure or success of the breeding attempt. For instance, nest placement affects the radiative environment and thus survival of eggs and nestlings (Walsberg 1981). Nest placement also affects the likelihood of preda-tion upon eggs and nestlings (e.g., Robertson
We provide substantial new information on the breeding biology of the Rusty-breasted Antpitta (Gr... more We provide substantial new information on the breeding biology of the Rusty-breasted Antpitta (Grallaricula ferrugineipectus ferrugineipectus) from 40 nests during four consecutive breeding seasons at Yacambú National Park in Venezuela. Vocalizations are quite variable in G. ferrugineipectus. Nesting activity peaked in April when laying began for half of all nests monitored. The date of nest initiation pattern suggests this species is single-brooded. Both parents incubate and the percent of time they incubate is high (87-99%) throughout the incubation period. The incubation period averaged (Ϯ SE) 17.0 Ϯ 0.12 days, while the nestling period averaged 13.37 Ϯ 0.37 days. G. f. ferrugineipectus has the shortest developmental time described for its genus. Time spent brooding nestlings decreased as nestlings grew, but was still greater at pin feather break day than observed in north temperate species. The growth rate constant based on mass (k ϭ 0.41) and tarsus length (k ϭ 0.24) was lower than the k for north temperate species of similar adult mass. All nesting mortality was caused by predation and overall daily survival rate (Ϯ SE) was relatively low (0.94 Ϯ 0.01) yielding an estimated 15% nest success.
... 262-265 "Snorkeling" by the Chicks of the Wattled J... more ... 262-265 "Snorkeling" by the Chicks of the Wattled Jacana Carlos Bosque"-3 and Emilio A. Herrera2 ... Statistical analyses were done with SYSTAT 7.0 for Windows (Wilkinson 1997). Mean relative position of the nostrils dif-fered between species (Fig. ...
For those few bird species that are exclusively frugivorous, the low protein content of fruits is... more For those few bird species that are exclusively frugivorous, the low protein content of fruits is likely a major nutritional constraint. Physiological mechanisms that allow strict frugivory remain enigmatic, but reduced protein requirements may suffice. We investigated protein requirements of Pesquet's Parrot (Psittrichas fulgidus), a highly specialized, obligate frugivore. Three isocaloric, fruit-based diets of varying protein content (6.1, 3.3, and 2.6% dry mass crude protein) were used in feeding trials lasting three to five days per diet. A minimum dietary protein requirement of 3.2% dry mass was estimated from balance trials. Endogenous nitrogen losses were 0.05 gN kg Ϫ0.75 day Ϫ1 and nitrogen equilibrium occurred at 0.32 gN kg Ϫ0.75 day Ϫ1. Those values are extremely low compared to those of granivorous and omnivorous bird species, but higher than those of nectarivorous species. In terms of nitrogen losses and requirements, Pesquet's Parrot most closely parallels the highly frugivorous Cedar Waxwing (Bombycilla cedrorum). Thus, reduced protein requirements appear to play an important physiological role in ability of highly frugivorous birds to subsist on fruit diets.
Mousebirds (Coliiformes) are unusual in having an exclusively vegetarian diet that includes subst... more Mousebirds (Coliiformes) are unusual in having an exclusively vegetarian diet that includes substantial foliage and by using huddling and sunning to assist thermoregulation. Although previous studies have identified plant species and plant parts consumed by mousebirds, the relative importance of different food types in the diet of wild birds has not been investigated. Furthermore, there is limited information on the extent and importance of their sunning behaviour in the field. We investigated the diet and time-activity budget of White-backed Mousebirds Colius colius at a coastal site in Western Cape province, South Africa. Their diet consisted mostly of leaves (56% of items) and fruits (39%), but diet composition varied with time. Leaves had significantly higher protein content than fruits. White-backed Mousebirds spent most of their time (96%) in stationary activities, particularly sunning (60%), and allocated little time to feeding (4%). However, the proportion of time spent on different activities varied with weather conditions and ambient temperature. When sunning, birds oriented their ventral parts towards the sun 93% of the time, suggesting that exogenous heating may be important for digestion.
Reverse mounting, females mounting males, is a widespread but uncommonly reported behaviour among... more Reverse mounting, females mounting males, is a widespread but uncommonly reported behaviour among birds. Although its function is not fully understood, it is generally accepted that reverse mounting is an integral part of courtship during pair bonding and mating. It has been reported in species of at least 10 orders, but only among three species of columbids previously. Here, I report a casual observation of reverse mounting by two individuals of Spot-winged Pigeons Patagioenas maculosa in the vicinity of the city of Córdaba, Argentina. Components of the display observed in the copulatory sequence of the pair, are frequent in the repertoire of displays during mating and courtship of columbids; yet, reverse mounting is seldom described. These observations support and extend the occurrence of reverse mounting in pigeons.
Global-scope scientific journals have played an important role in upholding a colonial legacy of ... more Global-scope scientific journals have played an important role in upholding a colonial legacy of north-south inequities in ornithology, and they now have a key role to play in increasing equity in scientific publishing. We explore common barriers faced by ornithologists in the Neotropics (Latin America and the Caribbean) and suggest priority actions that Ornithological Applications, Ornithology, and other global-scope ornithological journals can take to increase equity in publication and research uptake. Among the most important problems, we identified (1) restrictive (and north-biased) criteria for assessing research “importance” and “novelty,” (2) the high publication costs of the Author Pay (Gold) Open Access model, (3) language hegemony, (4) under-representation of ornithologists from the Neotropics on editorial boards and as lead authors on invited articles, and (5) lack of attention to ethics of collaboration and citation. We recommend that Ornithological Applications, Ornitho...
A major barrier to advancing ornithology is the systemic exclusion of professionals from the Glob... more A major barrier to advancing ornithology is the systemic exclusion of professionals from the Global South. A recent special dossier, Advances in Neotropical Ornithology, and a shortfalls analysis therein, unintentionally followed a long-standing pattern of highlighting individuals, knowledge, and views from the Global North, while largely omitting the perspectives of people based within the Neotropics. Here, we review problems with assessing the state of Neotropical ornithology through a northern lens, including discovery narratives, incomplete (and biased) understanding of history and advances, and the promotion of agendas that, while currently popular in the north, may not fit the needs and realities of Neotropical research. We argue that future advances in Neotropical ornithology will critically depend on identifying and addressing the systemic barriers that hold back ornithologists who live and work in the Neotropics: unreliable and limited funding, exclusion from international ...
... Open Access Subscription Access. Font Size: Small Medium Large. Short Note Opportunistic bloo... more ... Open Access Subscription Access. Font Size: Small Medium Large. Short Note Opportunistic blood-drinking by Black Crake Amaurornis flavirostris. Carlos Bosque. Abstract. No Abstract. Ostrich 2009, 80(1): 65. Full Text: PDF Ostrich: Journal of African Ornithology. ...
Background: Steatornis caripensis (the oilbird) is a very unusual bird. It supposedly never sees ... more Background: Steatornis caripensis (the oilbird) is a very unusual bird. It supposedly never sees daylight, roosting in huge aggregations in caves during the day and bringing back fruit to the cave at night. As a consequence a large number of the seeds from the fruit they feed upon germinate in the cave and spoil. Methodology/Principal Findings: Here we use newly developed GPS/acceleration loggers with remote UHF readout to show that several assumptions about the behaviour of Steatornis caripensis need to be revised. On average, they spend only every 3rd day in a cave, individuals spent most days sitting quietly in trees in the rainforest where they regurgitate seeds. Conclusions/Significance: This provides new data on the extent of seed dispersal and the movement ecology of Steatornis caripensis. It suggests that Steatornis caripensis is perhaps the most important long-distance seed disperser in Neotropical forests. We also show that colony-living comes with high activity costs to i...
Background: Steatornis caripensis (the oilbird) is a very unusual bird. It supposedly never sees ... more Background: Steatornis caripensis (the oilbird) is a very unusual bird. It supposedly never sees daylight, roosting in huge aggregations in caves during the day and bringing back fruit to the cave at night. As a consequence a large number of the seeds from the fruit they feed upon germinate in the cave and spoil. Methodology/Principal Findings: Here we use newly developed GPS/acceleration loggers with remote UHF readout to show that several assumptions about the behaviour of Steatornis caripensis need to be revised. On average, they spend only every 3rd day in a cave, individuals spent most days sitting quietly in trees in the rainforest where they regurgitate seeds. Conclusions/Significance: This provides new data on the extent of seed dispersal and the movement ecology of Steatornis caripensis. It suggests that Steatornis caripensis is perhaps the most important long-distance seed disperser in Neotropical forests. We also show that colony-living comes with high activity costs to i...
∙ In non‐migratory birds the annual cycle is composed of two critical events, breeding and molt,... more ∙ In non‐migratory birds the annual cycle is composed of two critical events, breeding and molt, spaced by quiescent periods. Breeding in arid environments is frequently dependent on rainfall, but arid environments have unpredictable and irregular precipitation; therefore, birds of arid environments are thought to maintain their reproductive system in a partially or fully activated state to responding rapidly to favorable conditions. Molt most commonly follows the end of reproduction. We studied the annual cycle of the Common Ground‐dove ( Columbina passerina ) for 15 months in arid scrub of Venezuela by determining gonadal sizes and maturation state, and by scoring wing, tail and body molt. As expected, both sexes underwent a brief period of gonadal regression of only about one month during the dry season, and maintained a partly or fully active reproductive system during the rest of the year. Breeding of Common Ground‐doves was associated to rainfall, but not exclusively so; test...
The Disassortative Pollen Flow Hypothesis proposed by Darwin postulates that the relative positio... more The Disassortative Pollen Flow Hypothesis proposed by Darwin postulates that the relative position of anthers and stigmas in distylous flowers enhances pollen flow between flowers of different morphs (legitimate pollination), in comparison to flow between flowers of the same morph (illegitimate pollination). In order to test this hypothesis, we measured pollen transport, mediated by a trained Copper-rumped Hummingbird (Amazilia tobaci), between flowers of the distylous Palicourea fendleri under laboratory conditions. In individual tests, we offered to the hummingbird a pollen donor flower and two emasculated recipient flowers in a controlled sequence. After each foraging bout, we counted the number of pollen grains transported from the donor flower to the stigmas of both recipient flowers. In agreement with Darwin's hypothesis, we found that hummingbirds transport pollen of "pin" flowers in significantly higher numbers to legitimate "thrum" stigmas, even if p...
Post-breeding migration of Oilbirds. -There are few indications in the literature suggesting that... more Post-breeding migration of Oilbirds. -There are few indications in the literature suggesting that Oilbirds (Steatornis caripensis) perform a post-reproductive migration, leaving their breeding caves at the end of the breeding season. Indirect evidence comes from the obser-vations ...
Causes of interspecific variation in growth rates within and among geographic regions remain poor... more Causes of interspecific variation in growth rates within and among geographic regions remain poorly understood. Passerine birds represent an intriguing case because differing theories yield the possibility of an antagonistic interaction between nest predation risk and food delivery rates on evolution of growth rates. We test this possibility among 64 Passerine species studied on three continents, including tropical and north and south temperate latitudes. Growth rates increased strongly with nestling predation rates within, but not between, sites. The importance of nest predation was further emphasized by revealing hidden allometric scaling effects. Nestling predation risk also was associated with reduced total feeding rates and per-nestling feeding rates within each site. Consequently, faster growth rates were associated with decreased per-nestling food delivery rates across species, both within and among regions. These relationships suggest that Passerines can evolve growth strategies in response to predation risk whereby food resources are not the primary limit on growth rate differences among species. In contrast, reaction norms of growth
All in-text references underlined in blue are linked to publications on ResearchGate, letting you... more All in-text references underlined in blue are linked to publications on ResearchGate, letting you access and read them immediately.
Selection of a suitable nesting site may deter-mine failure or success of the breeding attempt. F... more Selection of a suitable nesting site may deter-mine failure or success of the breeding attempt. For instance, nest placement affects the radiative environment and thus survival of eggs and nestlings (Walsberg 1981). Nest placement also affects the likelihood of preda-tion upon eggs and nestlings (e.g., Robertson
We provide substantial new information on the breeding biology of the Rusty-breasted Antpitta (Gr... more We provide substantial new information on the breeding biology of the Rusty-breasted Antpitta (Grallaricula ferrugineipectus ferrugineipectus) from 40 nests during four consecutive breeding seasons at Yacambú National Park in Venezuela. Vocalizations are quite variable in G. ferrugineipectus. Nesting activity peaked in April when laying began for half of all nests monitored. The date of nest initiation pattern suggests this species is single-brooded. Both parents incubate and the percent of time they incubate is high (87-99%) throughout the incubation period. The incubation period averaged (Ϯ SE) 17.0 Ϯ 0.12 days, while the nestling period averaged 13.37 Ϯ 0.37 days. G. f. ferrugineipectus has the shortest developmental time described for its genus. Time spent brooding nestlings decreased as nestlings grew, but was still greater at pin feather break day than observed in north temperate species. The growth rate constant based on mass (k ϭ 0.41) and tarsus length (k ϭ 0.24) was lower than the k for north temperate species of similar adult mass. All nesting mortality was caused by predation and overall daily survival rate (Ϯ SE) was relatively low (0.94 Ϯ 0.01) yielding an estimated 15% nest success.
... 262-265 "Snorkeling" by the Chicks of the Wattled J... more ... 262-265 "Snorkeling" by the Chicks of the Wattled Jacana Carlos Bosque"-3 and Emilio A. Herrera2 ... Statistical analyses were done with SYSTAT 7.0 for Windows (Wilkinson 1997). Mean relative position of the nostrils dif-fered between species (Fig. ...
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