ABSTRACT Brazil is home to many mountain ranges which harbor diverse avifauna. However, studies on the altitudinal distribution of Brazilian birds are still few and many have never been published, hampering both the dissemination of basic information and conservation actions. Here we present a critical review of ornithological studies undertaken in Brazilian mountain ranges, and propose a classification of geographic scope, altitudinal gradient, and methodology. Since 1922, 184 ornithological studies included altitude in some way in Brazil, encompassing a variety of research topics and species. About a quarter of these studies were never published in peer-reviewed journals, and 39% do not provide basic data on elevation nor link the bird species with sampling plots, thus limiting their applicability. The majority of studies are concentrated (83%) in southern and southeastern Brazil, especially in the Serra do Mar range, and so most data are associated with the Atlantic Forest. Gaps remain in other regions, such as Amazonia (Pantepui region). Most studies either did not sample the entire elevation gradient, were not standardized, lacked explicit hypothesis, or did not account for a seasonal sampling embracing the four seasons of the year, so interpretation of the observed patterns remains difficult. With this compilation, we organize the available information and point to future altitudinal research on birds, in addition to highlighting the importance of preserving habitats along altitudinal gradients in the mountainous regions in Brazil.

ABSTRACT Birds’ seasonal altitudinal movements in Brazil are poorly understood. The main source of information and has fostered interest since the 1980s. However, most of the available information is anecdotal, sources are repeatedly cited, and the information provided is quite superficial and speculative. Through bibliographic searches, we found 107 studies, 83 (77%) of which we consider valid, and only 63 (59%) were peer-reviewed. Most studies were carried out in southern and southeastern Brazil. Only 11 studies explicitly addressed seasonal altitudinal movements. Surprisingly, none of the studies simultaneously comprised a full year of study, standardized sampling methods, and encompassed the entire altitudinal range through which the birds might have moved. As a consequence, the quality of the data is questionable, and the expression “altitudinal migration” is unlikely to be accurate and has never been unequivocally demonstrated for birds in Brazil. Mention of “altitudinal migration” was found for 68 bird species, but these must be more clearly defined and appropriately tested.

ABSTRACT Altitudinal migration in birds comprises seasonal movements between breeding and non-breeding areas in mountainous regions, attributed to biotic and abiotic factors. Different authors have suggested the existence of altitudinal migration between high and low areas of the mountains of the Atlantic Forest, with movement from high to low during the winter when birds would be fleeing the cold and in search of food, but there is no documented evidence. Through recaptures of understory birds, we investigated possible altitudinal migration in a region of the Atlantic Forest in Southeast Brazil. Twenty mist-nets were set at four locations between 15 and 729 m a.s.l. during 143 days of field work, distributed over 54 months and covering all seasons of the year. A total of 1946 birds (98 species) were captured/banded with 558 being recaptured (28.6%; 45 species). However, only 42 of the recaptures were at a different elevation. Most of the movements were of short distances and performed only once by birds, showing no seasonal pattern. These movements may be better interpreted as daily movements undertaken by birds of mixed-species flocks looking for food or moving around their respective home-ranges. Our results show that mist-nets may not be an effective tool in detecting altitudinal movements of birds and that other methods should be evaluated for this purpose.