I correlated the plasma titers of testosterone (T), estradiol (E), luteinizing hormone (LH), progesterone (P), corticosterone (B) and prolactin (Prl) with the reproductive behavior of breeders and adult and juvenal-plumaged helpers of the Harris' Hawk. During nest building, breeding males and adult male helpers had higher T levels than those in immature male helpers. Among females, only breeders had elevated T levels during nest building. During nest building, breeding females had higher E levels than those in adult and immature females helpers. Patterns of LH were similar to those of T and E. Concentrations of P and B varied only with handling time. During incubation, Prl titers were elevated only in breeding males and females. In contrast to other altricial species, all breeders showed no elevation in Prl levels during feeding of young. Among males, adult male helpers had the highest Prl levels while feeding young.

Total body electrical conductivity (TOBEC) is a noninvasive method for the estimation of lean mass in live subjects. Lipid content can be calculated from the body mass measured and the lean mass estimated from TOBEC. I used live American Kestrels (Falco sparverius) to study the accuracy of this method. TOBEC measurements were compared to actual body content determined by Soxhlet fat extraction using petroleum ether as the solvent. TOBEC estimated 73.7% of the variation in lean mass in a sample of 21 kestrels. The use of restraining devices (Vetrap and cardboard cylinders) altered the TOBEC measurement but only by an average of 1.92% and 0.83%, respectively. TOBEC estimated 83.8% of the vii variation in lean mass for 21 kestrel carcasses warmed to 39.8°C. No significant difference was found between the slope or elevation of the calibration lines developed using live or dead kestrels. A significant difference was found between measurements taken at two different positions. Body temperature altered the TOBEC measurements by an average of 1.54% (SE = 0.55) for each 1°C change over a temperature range of 7.0°C (37.3-44.4). The calibration line developed for kestrels was used to estimate lean mass and compute fat mass of migrating kestrels, Sharp-shinned Hawks (Accipiter striatus) and Merlins (Falco columbarius). The average percent fat mass of kestrels trapped during migration at Cape May, New Jersey, was 6.01 % (SE = 1.92, n = 1 2) for males and 8.51 % (SE = 2.00, n = 13) for females. The difference in lean mass between male and female, and between early, mid-season, and late migrating Sharp-shinned Hawks differed significantly during migration. The fat mass of Sharp-shinned Hawks averaged 5.55% (SE = 0.94, n = 53) for males and 10.92% (SE = 0.80, n = 87) for females. Male Merlins had an average fat mass of 18.05% (SE = 3.35, n = 7) and females averaged 14.19% (SE = 3.15, n = 8).

Thesis (M.S.) -- Mississippi State University. Department of Wildlife and Fisheries. / Title from title screen. Includes bibliographical references.

Food-searching behavior of two adult male Ferruginous Hawks (Buteo regalis) was studied by direct observation in Curlew Valley, Utah-Idaho, during the nesting seasons of 1974 and 1975. This paper analyzes the effects of vegetation type, prey distribution, cover density, previous experience, and time and energy budgets upon the predators' choice of hunting methods and hunting sites. Both hawks hunted actively throughout the day (0600 to 2100 hours MDT). Male 1 (1974) and Male 2 (1975) captured an average of 8.7 ± 2.0 and 9.0 ± 1.5 prey items per day, respectively, during the 4-wk observation period in each year. The hawks hunted by four distinguishable methods: (1) from a perch, (2) from the ground, (3) from low-altitude (active) flight, and (4) from high-altitude (soaring) flight. The birds made a total of 808 observed strikes and were successful in securing prey in 129 (16.6 percent) of those strikes. Success rate (successful strikes/total attempted strikes) varied significantly with hunting method. The hawks were selective in their use of vegetation types for hunting. Both birds used the "bare ground" and "pasture" types more than expected by chance. Male 2 also over-used the "alfalfa" type. Both hawks significantly under-used the "grass-shrub," "grass or grain," "old field," "juniper," and "rush-grass" cover types. The differences in use of vegetation types could not be related to differences in prey biomass. The birds were selective in their use of areas which differed in density of vegetative cover. Areas with no cover were used by both hawks more than expected by chance; all other areas were under-used with the single exception of "dense" cover in 1975. Previous experience was important to the birds' choice of hunting sites and hunting methods. Each hawk returned directly to the site of its last prey capture on more than half of its hunting forays. Similarly, each hawk tended to initiate a new hunting effort by using the hunting method that had been successful on its previous hunt. In 1975, Male 2 switched its emphasis to a new major hunting area during the fourth week of observation. The apparent reason for the switch was a decline in success at the first hunting area due to the growth of vegetation which concealed prey. Males 1 and 2 averaged 0.94 ± 0.43 and 1.27 ± 0.55 prey captures per hour of hunting time, respectively. Capture rates (captures/time) varied with hunting method. The amount of time a hawk spent hunting by each method was not related to its capture rate by that method. However, each bird's total use of sit-and-wait hunting (from a perch or from the ground) and of hunting from low-altitude flight was proportional to estimates of the number of captures per unit of energetic cost for those methods. Both hawks hunted from high-altitude flight more than expected on the basis of their catch/cost ratios for that technique. This suggests that soaring was not exclusively a hunting technique, but that it had some additional purpose unrelated to food gathering. There was some evidence that the hawks used major hunting sites which provided high benefit/cost ratios relative to the rest of their foraging ranges. Both hawks foraged efficiently by concentrating more of their foraging time on the hunting method and in the hunting sites which yielded the highest number of prey captures per unit of energy ex-pended. The birds' use of secondary hunting areas may have contributed to their long-term foraging efficiency by informing them of changes in the foraging potential of different portions of their home ranges. Such flexible foraging patterns may be critical to the survival of predators which rely on highly variable small-mammal populations.

During the 1979 breeding season four pairs of northern harriers, or marsh hawks (Circus cyaneus) and four pairs of short-eared owls (Asio flammeus) were studied in Cache Valley, Utah. The study was concerned solely with diurnal resource utilization, and did not examine the owls' nocturnal activities. The home range of each harrier pair overlapped substantially with that of an owl pair. Percent habitat overlap for hawk-owl pairs varied from 39 percent to 72 percent. Observations were made to determine if differences existed in their utilization of habitat and food resources, or in their daily and seasonal activity patterns. Both species utilized mainly wet old field and pasture habitat types for their hunting efforts. In general wet old fields were utilized more than expected based on their availability, while pasture, bare ground, and harvested field habitats were used less than expected. Pairs of hawks and owls sharing common habitats generally showed differences in preferred hunting habitats. An analysis of variance showed that hawks and owls were making strikes in different habitat types and to some extent in different parts of the habitat. Harriers and owls nested in different habitat types. Breeding seasons of the two species overlapped almost totally, but interspecific differences were detected in time-activity budgets. Overall, the owls were more sedentary than the hawks. Both species spent approximately 10 percent of the day in hunting-related activites, but timing of hunting varied from pair to pair. Overlapping pairs generally differed in their daily distribution of hunting time. The analysis of variance showed that there was a significant difference in the timing of strikes made by harriers and owls. Both species were feeding primarily on small mammals in the study area, and food resources were probably not a limiting factor for either population. Though northern harriers and short-eared owls appear to have a high degree of niche overlap, this study showed that where eight individual pairs of the two species came into contact they differed in time-activity budgets and habitat utilization. Coexistence between these two species may be enhanced by the fact that they both feed on an abundant prey resource. By subtle habitat and time budget preferences, reinforced through interspecific aggression, they can avoid competition.

During the spring seasons of 1967 and 1968 ecological studies were made of nesting Ferruginou.s Hawks (Buteo regalis) in a 325 square mile area in west-central Utah. In the springs of 1967 and 1968 a systematic search was conducted throughout the study area for Ferruginous Hawk nests. When active nests were located they were kept under observation throughout the study. The density of nesting pairs in 1967 and 1968 ranged from 7 to 15.4 square miles per pair. An annual seasonal displacement was exhibited, with Ferruginous Hawks being present in the study area only during the nesting season, which lasted from early March until early September. Nest locations implied a preference to inhabit particular areas. The distance separating neighbors in 1967 and 1968 varied from 2.3 miles to .4 miles. More than ninety percent of the pairs observed attended more than one nest; such supernumerary nests averaged 2.5 per pair. The majority of nests were constructed on the ground. More than half of the nests faced south; only about one-tenth faced north. The typical nest was composed of large sticks, lined with bark , grass, and paper, and had an average diameter of 39 inches, a thickness of 17 inches, a pocket diameter of 14 inches, and a pocket depth of 3 inches. Both members of each pair of hawks were active in nest building, which began in early March. In 1967 thirteen nests produced 20 eggs (1.5 eggs per nest) and 8 young (.67 percent), of which 8 (100 percent) fledged (.67 per nest); in 1968 fourteen nests produced 50 eggs (3.57 eggs per nest) and 33 young (2.36 per nest), of which 28 (85 percent) fledged (2 per nest). Territorial behavior was inconsistent. On occasion each nesting pair was seen to actively defend its territory against other predatory birds; whereas on other occasions intruding raptors met no resistance from the resident pair of Ferruginous Hawks. From 26 eyries, 283 prey individuals were identified. Mammals (92 percent) predominated. The Ord's Kangaroo Rat (Dipodomys ordii) was the most numerous prey species (44 percent), with the Blacktail Jackrabbit (Lepus californicus) being the next most common (30 percent). Birds represented 5 percent of the total prey. Several hunting techniques were exhibited by the hawks. Hunting was usually conducted before sunrise and after sunset each day. Recorded mortality was minimal, with only one dead Ferruginous Hawk observed during the study.

Telemetry triangulation provides an estimate of a radio-tagged animal’s location that is influenced by various time and site-specific factors that can cause errors. If these errors are not considered when using location data, the conclusions drawn about animal behavior such as habitat use might be misleading. I determined home range and habitat use and selection characteristics of red-shouldered hawks (Buteo lineatus) in central Maryland. The effects of telemetry triangulation errors on these characteristics were examined. Red-shouldered hawk location estimates were obtained by triangulation to radio-tagged birds. Point estimates were determined by using ≥3 azimuths. A confidence ellipse was calculated around each point estimate which represented the error area associated with that point estimate. From the distribution of possible points within the error area of each point estimate, sampled points (simulated points) were generated for use in additional analyses to assess telemetry error. Home range sizes, based on point estimates and simulated point estimates were delineated using the convex polygon and harmonic mean models. Habitat occurrence was described from a digitized cover type map. Average home range sizes based on point estimates and simulated point estimates for 3 male hawks were larger than average home range areas for 2 female hawks. There were differences detected between pooled point estimate home range sizes and the pooled simulated point estimate home range sizes. There were fewer differences in home range sizes based on the harmonic mean model than the convex polygon. No significant seasonal differences were found for point estimate or simulated point estimate home range Sizes. Seasonal habitat use did not vary based on pooled data from all hawks on PWRC. Bottomland forest was the most frequently used habitat type; however, water habitats (ponds and river) were the most frequently selected. Bottomland forests, river swamps, terrace/bluff forests, residential/structural areas, seepage swamps, pine forests, and pine/oak forests were selected occasionally by most hawks. The two most infrequently selected habitats were powerlines and upland oak forests. / Master of Science

A família Accipitridae representa uma das maiores radiações de aves atuais, ocupando habitats diversos em grande parte do planeta. Entre as divisões propostas para a família no passado, o grupo dos gaviões buteoninos figura entre um dos poucos que se aproximam em composição a uma linhagem monofilética, de acordo com análises filogenéticas recentes. Além de ocorrer tanto no Novo Mundo como no Velho Mundo, a maior parte das espécies de gaviões buteoninos está concentrada na América do Sul e na América Central, o que os torna um modelo atrativo para a análise de padrões e processos de diversificação em escalas continental e local. Outro aspecto interessante do grupo é o grande número de espécies migratórias, padrão ainda pouco explorado sob uma perspectiva filogenética. Os principais objetivos deste trabalho foram inferir as relações filogenéticas entre as espécies de gaviões buteoninos, analisar a evolução do comportamento migratório no grupo, e inferir padrões e processos de diversificação, com ênfase na região Neotropical. Foram utilizados mais de 7.000 pares de base de DNA mitocondrial e nuclear de 51 espécies de gaviões buteoninos, compreendendo o maior estudo filogenético do grupo até o momento. Do total de seqüências utilizadas, cerca de um terço foi representado por seqüências de DNA do 12S, tRNAVal e 16S, que contém uma proporção de sítios de evolução dependente resultante da existência de uma estrutura secundária. Como forma de avaliar o impacto destes sítios nas estimativas, foram também realizadas análises alternativas que incorporaram informação de estrutura secundária. Devido à indisponibilidade de um modelo de estrutura secundária de 16S para aves, este foi aqui elaborado com base em uma análise comparativa de representantes de todas as ordens de aves atuais. Os resultados sugerem que os gêneros Buteo, Leucopternis e Buteogallus como atualmente reconhecidos não são monofiléticos, o que ressalta a falta de concordância entre a classificação atual e a histórica evolutiva do grupo. Cinco linhagens principais foram encontradas, sendo a base da árvore composta por espécies predominantemente neotropicais, e a porção mais derivada principalmente por espécies neárticas e do Velho Mundo. Este resultado, associado às estimativas de tempo de divergência, sugere um longo período de diversificação na região Neotropical (com início entre o Oligoceno Superior ou o Mioceno, e se estendendo até o Pleistoceno), com colonização e diversificação recentes na região Neártica e no Velho Mundo (com início no Mioceno Superior ou no Plioceno, se estendendo até o Pleistoceno). O comportamento migratório evoluiu diversas vezes, e pode ter contribuído para a diversificação de algumas espécies, ao possibilitar a colonização de habitats antes não ocupados e promover especiação em ilhas. Na região Neotropical, disjunções de espécies de florestas de terras baixas que ocupam áreas a leste e oeste dos Andes ocorreram quatro vezes, possivelmente em dois eventos vicariantes. As disjunções mais antigas podem ter sido causadas pelo soerguimento da cordilheira, enquanto não foi possível definir claramente os processos envolvidos nas especiações mais recentes. Foram encontradas duas linhagens distribuídas em habitats alagados e ripários. Os resultados sugerem não somente um longo processo de diversificação, de forma independente das espécies de florestas não alagadas, mas também conexões históricas entre florestas de várzea da Amazônia e habitats costeiros. Espécies florestais e de áreas abertas não são reciprocamente monofiléticas. De forma similar, em alguns casos, espécies pertencentes a um mesmo bioma não são proximamente relacionadas, o que sugere uma história complexa de diversificação na região. A utilização de dados de sítios emparelhados de seqüências de RNA não trouxe mudanças significativas nas topologias e inferências de tempo de divergência, possivelmente devido à baixa variação das hastes neste grau de divergência. / The family Accipitridae represents one of the largest radiations of modern birds, with species being found in a plethora of habitats around the world. Among the divisions proposed for the family in the past, the group of the buteonine hawks is one of the few that approximate monophyletic lineages, according to recent phylogenetic analyses. Besides occurring both in the New World and Old World, most buteonine hawk species are mainly found in Central and South America, what provides an opportunity to evaluate patterns and processes of diversification in both continental and local scales. The main goals of this work were to infer phylogenetic relationships among species of buteonine hawks, analyze the evolution of migratory behaviour, and evaluate patterns and processes of diversification, especially in the Neotropical region. We obtained more than 7.000 base pairs of mitochondrial and nuclear DNA sequences from 51 species of buteonine hawks, what comprises the largest phylogenetic analysis of the group so far. Approximately one third of the total dataset was obtained from DNA sequences of 12S, tRNAVal and 16S, which are known to have paired sites that evolve in concert due to the presence of a secondary structure. Alternative analyses incorporating such information have been performed, as a way to evaluate the effects of secondary structure in the phylogenetic analyses. Since a model of secondary structure of 16S of birds was not available so far, we build one based on comparative analysis of representatives of all modern avian orders. The results suggest that the genera Buteo, Leucopternis and Buteogallus as currently accepted are not monophyletic, what stress a lack of concordance between current classification and the evolutionary history of this group. Five main lineages were found, and the most basal part of the topology is composed by mainly neotropical species, while the majority of neartic and Old World species were positioned in the most derived part of the tree. Together with divergence time estimates, those results suggest a long period of diversification in the Neotropics (possibly beginning in the Upper Miocene or Oligocene, and extending to the Pleistocene), with a latter colonization and diversification of the Neartics and Old World (possibly beginning between the Upper Oligocene or Pliocene, and extending to the Pleistocene). Migratory behaviour evolved several times, and may have contributed to diversification by means of exploitation of previously unavailable habitats as well as promotion of speciation in islands. Lowland species disjunctions between each side of the Andes occurred four times, possible due to two vicariant events. The earliest disjunctions may have been caused by Andean orogeny, but no process could be clearly attributed to the two most recent speciations. Two lineages restricted to flooded habitats were found. The results suggest not only a long process of diversification in such habitats, independently of species of non-flooded habitats, but also a historical relationship between várzea forests in Amazonia and costal habitats. Similarly, species that occupy the same biome are not the closest relatives in several cases, what suggests a complex history of diversification in the Neotropical region. Inclusion of secondary structure information did not affect significantly phylogenetic and divergence time estimates, likely due to the low variation in stems in such level of divergence.

Total body electrical conductivity (TOBEC) is a noninvasive method for the estimation of lean mass in live subjects. Lipid content can be calculated from the body mass measured and the lean mass estimated from TOBEC. I used live American Kestrels (Falco sparverius) to study the accuracy of this method. TOBEC measurements were compared to actual body content determined by Soxhlet fat extraction using petroleum ether as the solvent. TOBEC estimated 73.7% of the variation in lean mass in a sample of 21 kestrels. The use of restraining devices (Vetrap and cardboard cylinders) altered the TOBEC measurement but only by an average of 1.92% and 0.83%, respectively. TOBEC estimated 83.8% of the variation in lean mass for 21 kestrel carcasses warmed to 39.8oC. No significant difference was found between the slope or elevation of the calibration lines developed using live or dead kestrels. A significant difference was found between measurements taken at two different positions. Body temperature altered the TOBEC measurements by an average of 1.54% (SE = 0.55) for each 10C change over a temperature range of 7.00C (37.3-44.4). The calibration line developed for kestrels was used to estimate lean mass and compute fat mass of migrating kestrels, Sharp-shinned Hawks (Accipiter striatus) and Merlins (Fa/co co/umbarius). The average percent fat mass of kestrels trapped during migration at Cape May, New Jersey, was 6.01 % (SE = 1.92, n = 1 2) for males and 8.51 % (SE = 2.00, n = 13) for females. The difference in lean mass between male and female, and between early, mid-season, and late migrating Sharp-shinned Hawks differed significantly during migration. The fat mass of Sharp-shinned Hawks averaged 5.55% (SE = 0.94, n = 53) for males and 10.92% (SE = 0.80, n = 87) for females. Male Merlins had an average fat mass of 18.05% (SE = 3.35, n = 7) and females averaged 14.19% (SE = 3.15, n = 8).

A família Accipitridae representa uma das maiores radiações de aves atuais, ocupando habitats diversos em grande parte do planeta. Entre as divisões propostas para a família no passado, o grupo dos gaviões buteoninos figura entre um dos poucos que se aproximam em composição a uma linhagem monofilética, de acordo com análises filogenéticas recentes. Além de ocorrer tanto no Novo Mundo como no Velho Mundo, a maior parte das espécies de gaviões buteoninos está concentrada na América do Sul e na América Central, o que os torna um modelo atrativo para a análise de padrões e processos de diversificação em escalas continental e local. Outro aspecto interessante do grupo é o grande número de espécies migratórias, padrão ainda pouco explorado sob uma perspectiva filogenética. Os principais objetivos deste trabalho foram inferir as relações filogenéticas entre as espécies de gaviões buteoninos, analisar a evolução do comportamento migratório no grupo, e inferir padrões e processos de diversificação, com ênfase na região Neotropical. Foram utilizados mais de 7.000 pares de base de DNA mitocondrial e nuclear de 51 espécies de gaviões buteoninos, compreendendo o maior estudo filogenético do grupo até o momento. Do total de seqüências utilizadas, cerca de um terço foi representado por seqüências de DNA do 12S, tRNAVal e 16S, que contém uma proporção de sítios de evolução dependente resultante da existência de uma estrutura secundária. Como forma de avaliar o impacto destes sítios nas estimativas, foram também realizadas análises alternativas que incorporaram informação de estrutura secundária. Devido à indisponibilidade de um modelo de estrutura secundária de 16S para aves, este foi aqui elaborado com base em uma análise comparativa de representantes de todas as ordens de aves atuais. Os resultados sugerem que os gêneros Buteo, Leucopternis e Buteogallus como atualmente reconhecidos não são monofiléticos, o que ressalta a falta de concordância entre a classificação atual e a histórica evolutiva do grupo. Cinco linhagens principais foram encontradas, sendo a base da árvore composta por espécies predominantemente neotropicais, e a porção mais derivada principalmente por espécies neárticas e do Velho Mundo. Este resultado, associado às estimativas de tempo de divergência, sugere um longo período de diversificação na região Neotropical (com início entre o Oligoceno Superior ou o Mioceno, e se estendendo até o Pleistoceno), com colonização e diversificação recentes na região Neártica e no Velho Mundo (com início no Mioceno Superior ou no Plioceno, se estendendo até o Pleistoceno). O comportamento migratório evoluiu diversas vezes, e pode ter contribuído para a diversificação de algumas espécies, ao possibilitar a colonização de habitats antes não ocupados e promover especiação em ilhas. Na região Neotropical, disjunções de espécies de florestas de terras baixas que ocupam áreas a leste e oeste dos Andes ocorreram quatro vezes, possivelmente em dois eventos vicariantes. As disjunções mais antigas podem ter sido causadas pelo soerguimento da cordilheira, enquanto não foi possível definir claramente os processos envolvidos nas especiações mais recentes. Foram encontradas duas linhagens distribuídas em habitats alagados e ripários. Os resultados sugerem não somente um longo processo de diversificação, de forma independente das espécies de florestas não alagadas, mas também conexões históricas entre florestas de várzea da Amazônia e habitats costeiros. Espécies florestais e de áreas abertas não são reciprocamente monofiléticas. De forma similar, em alguns casos, espécies pertencentes a um mesmo bioma não são proximamente relacionadas, o que sugere uma história complexa de diversificação na região. A utilização de dados de sítios emparelhados de seqüências de RNA não trouxe mudanças significativas nas topologias e inferências de tempo de divergência, possivelmente devido à baixa variação das hastes neste grau de divergência. / The family Accipitridae represents one of the largest radiations of modern birds, with species being found in a plethora of habitats around the world. Among the divisions proposed for the family in the past, the group of the buteonine hawks is one of the few that approximate monophyletic lineages, according to recent phylogenetic analyses. Besides occurring both in the New World and Old World, most buteonine hawk species are mainly found in Central and South America, what provides an opportunity to evaluate patterns and processes of diversification in both continental and local scales. The main goals of this work were to infer phylogenetic relationships among species of buteonine hawks, analyze the evolution of migratory behaviour, and evaluate patterns and processes of diversification, especially in the Neotropical region. We obtained more than 7.000 base pairs of mitochondrial and nuclear DNA sequences from 51 species of buteonine hawks, what comprises the largest phylogenetic analysis of the group so far. Approximately one third of the total dataset was obtained from DNA sequences of 12S, tRNAVal and 16S, which are known to have paired sites that evolve in concert due to the presence of a secondary structure. Alternative analyses incorporating such information have been performed, as a way to evaluate the effects of secondary structure in the phylogenetic analyses. Since a model of secondary structure of 16S of birds was not available so far, we build one based on comparative analysis of representatives of all modern avian orders. The results suggest that the genera Buteo, Leucopternis and Buteogallus as currently accepted are not monophyletic, what stress a lack of concordance between current classification and the evolutionary history of this group. Five main lineages were found, and the most basal part of the topology is composed by mainly neotropical species, while the majority of neartic and Old World species were positioned in the most derived part of the tree. Together with divergence time estimates, those results suggest a long period of diversification in the Neotropics (possibly beginning in the Upper Miocene or Oligocene, and extending to the Pleistocene), with a latter colonization and diversification of the Neartics and Old World (possibly beginning between the Upper Oligocene or Pliocene, and extending to the Pleistocene). Migratory behaviour evolved several times, and may have contributed to diversification by means of exploitation of previously unavailable habitats as well as promotion of speciation in islands. Lowland species disjunctions between each side of the Andes occurred four times, possible due to two vicariant events. The earliest disjunctions may have been caused by Andean orogeny, but no process could be clearly attributed to the two most recent speciations. Two lineages restricted to flooded habitats were found. The results suggest not only a long process of diversification in such habitats, independently of species of non-flooded habitats, but also a historical relationship between várzea forests in Amazonia and costal habitats. Similarly, species that occupy the same biome are not the closest relatives in several cases, what suggests a complex history of diversification in the Neotropical region. Inclusion of secondary structure information did not affect significantly phylogenetic and divergence time estimates, likely due to the low variation in stems in such level of divergence.