Psittaciformes are a very diverse group of non-passerine birds, with advanced cognitive abilities and highly developed locomotor and feeding behaviours. Using computed tomography and three-dimensional (3D) visualization software, the endocasts of 14 extant Neotropical parrots were reconstructed, with the aim of analysing, comparing and exploring the morphology of the brain within the clade. A 3D geomorphometric analysis was performed, and the encephalization quotient (EQ) was calculated. Brain morphology character states were traced onto a Psittaciformes tree in order to facilitate interpretation of morphological traits in a phylogenetic context. Our results indicate that: (i) there are two conspicuously distinct brain morphologies, one considered walnut type (quadrangular and wider than long) and the other rounded (narrower and rostrally tapered); (ii) Psittaciformes possess a noticeable notch between hemisphaeria that divides the bulbus olfactorius; (iii) the plesiomorphic and most frequently observed characteristics of Neotropical parrots are a rostrally tapered telencephalon in dorsal view, distinctly enlarged dorsal expansion of the eminentia sagittalis and conspicuous fissura mediana; (iv) there is a positive correlation between body mass and brain volume; (v) psittacids are characterized by high EQ values that suggest high brain volumes in relation to their body masses; and (vi) the endocranial morphology of the Psittaciformes as a whole is distinctive relative to other birds. This new knowledge of brain morphology offers much potential for further insight in paleoneurological, phylogenetic and evolutionary studies.

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While bird vocalizations (produced by the syrinx) have been the focus of countless studies, mechanical sounds (produced by external body structures) have received much less attention. In particular, the evolutionary interplay between these two modes of acoustic communication remains largely unstudied. Here, we present the first species‐level molecular phylogeny of the doraditos (Pseudocolopteryx), reconstruct the evolutionary history of acoustic vocal and non‐vocal characters, elucidate their relationship to feather modifications and aerial displays, and explore the influence of acoustics in the speciation of cryptic species. Our well‐resolved phylogeny using four genes (ND2, COI, MB and ODC), recovered the monophyly of Pseudocolopteryx, resolving the relationships among its five species: ((((P. sclateri) P. acutipennis) P. dinelliana) P. citreola, P. flaviventris). Repetition and translocation of acoustic elements were commonplace in the evolution of Pseudocolopteryx. Songs were composed of introductory syllables and a final flourish. Bill‐snapping sounds of P. sclateri were functionally homologous to introductory vocal syllables of the other species. The song of P. dinelliana evolved to high levels of complexity and repetition and is the syntactically most complex song in Pseudocolopteryx (and perhaps in the Tyrannidae). Aerial displays, mechanical wing sounds and modifications of primary feathers coevolved in three species: P. sclateri, P. acutipennis and P. dinelliana. Wing sounds documented for P. acutipennis and P. dinelliana differed markedly, and their production mechanisms might differ. The two cryptic and sibling species P. flaviventris and P. citreola diverged ∽60,000 Ya were not reciprocally monophyletic and are a case of extremely rapid evolutionary acoustic differentiation with morphological stasis.

Sexually dichromatic birds often show delayed plumage maturation, but second-year (SY) males may or may not be distinguishable from females. In competitive contexts, SY males receive a reduced amount of adult males’ aggression, either by mimicking females or through signaling their sex and inexperience as subordinate males. To the human eye, reproductive dull SY male Saffron Finches are indistinguishable from females, whereas after second-year (ASY) males are golden yellow. Our aim is to establish whether SY males are sexually dichromatic with females to the eye of conspecifics. We describe plumage variation in females, SY and ASY males and, in particular, analyze assortative mating by color by comparing a previously disregarded yellow feather patch shared by the three groups. We measured plumage reflectance of the forehead, breast, belly, and axillaries, and used a two-step avian visual model analysis to estimate the ability of Saffron Finches to distinguish between SY males and females. We find that those groups are indistinguishable to conspecifics by color. Furthermore, we find non-significant evidence of assortative mating directly related to the coloration of comparable feather patches between females and each type of male, though body condition of SY males is associated to that of their mates. Our results are compatible with both the female-mimicry and the status signaling hypotheses of evolution and maintenance of delayed plumage maturation. However, the singing behavior of males reveals their presence within the breeding site; the combined effect of song and dull coloration suggest that SY males are honestly revealing their sex and status to conspecifics.

The Amaurospiza ‘seedeaters’ are bamboo‐specialized mixed strategists, most often found in bamboos in vegetative state, feeding on buds, shoots, petioles and insects. As bamboos die after flowering, birds may wander in search of live vegetative bamboo. The three currently recognized species of Amaurospiza are allopatrically distributed: the Blackish‐blue Seedeater Amaurospiza moesta in the Atlantic Forest of Argentina, Brazil and Paraguay, and in forest enclaves in the Cerrado; the recently described Carrizal Seedeater Amaurospiza carrizalensis known from a few localities in southeastern Venezuela; and the Blue Seedeater Amaurospiza concolor distributed patchily from Mexico to Peru. Three subspecies are recognized within A. concolor: relicta in southwest Mexico, concolor from southern Mexico to Panama and aequatorialis from southwest Colombia to northwest Peru. Full species status has been advocated for relicta and aequatorialis but evidence supporting their recognition is weak, while relicta was described in the monospecific genus Amaurospizopsis. Here we (1) test the monophyly of Amaurospiza, (2) reconstruct the phylogenetic relationships of all its constituent taxa using mitochondrial and nuclear markers, (3) re‐assess species limits in Amaurospiza with the aid of vocalizations and genetic and plumage data, and (4) discuss the link between bamboo life history, biogeographical patterns and extent of genetic differentiation. Amaurospiza was found to be monophyletic in both the ND2 and multilocus analyses. In the ND2 tree A. moesta and A. carrizalensis were sister to each other, A. concolor was found to be paraphyletic because aequatorialis was placed as sister to moesta–carrizalensis, and a clade including nominate concolor and relicta was sister to all the other taxa. The multilocus tree showed the same relationships, but lacked nuclear samples of relicta. Mean ND2 pairwise distance between concolor and aequatorialis (8.3%) was greater than that between moesta and carrizalensis (5.7%), while relicta diverged on average 1.0% from nominate concolor. The South American clade has more slender bills and white underwing coverts, while the Central American clade has thicker bills and bluish underwing coverts. All taxa exhibited typical Amaurospiza songs with quickly delivered, warbled, pure and fairly high‐pitched musical notes. Number of inflections/second exhibited a stepped pattern, with concolor and relicta on the lower end and carrizalensis, aequatorialis and moesta on the upper end. Similarly, moesta, carrizalensis and aequatorialis had overall more inflections per note than concolor and relicta. Linear discriminant analysis using nine acoustic variables correctly assigned all 62 songs to the correct taxon. Morphology, plumage, vocalizations and phylogenetic data indicate that aequatorialis should be afforded full species status as the Ecuadorian Seedeater (A. aequatorialis), suggest keeping relicta as a subspecies of A. concolor and support continued recognition of A. carrizalensis. Our data support merging Amaurospizopsis into Amaurospiza.

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