How much do we know about the breeding biology of bird species in the world?

Abstract

Knowledge on species’ breeding biology is the building blocks of avian life history theory. A review for the current status of the knowledge at a global scale is needed to highlight the priority for future research. We collected all available information on three critical nesting parameters (clutch size, incubation period and nestling period) for the close to 10 000 bird species in the world and identified taxonomic, geographic and habitat gaps in the distribution of knowledge on avian breeding biology. The results show that only one third of all extant species are well known regarding the three nesting parameters analyzed, while the rest are partly or poorly known. Most data deficient taxonomic groups are tropical forest nesters, particularly from the Amazon basin, southeast Asia, Equatorial Africa and Madagascar – the places that harbor the world's highest bird diversity. These knowledge gaps could be hampering our understanding of avian life histories. Ornithologists are encouraged to pay more efforts to explore the breeding biology of those poorly‐known species.

Unnatural history: is a paradigm shift of natural history in 21st century ornithology needed?

“…However, we feel it is worth revisiting the complementary role of natural history in ornithology to better understand its role in the conservation and management of avian populations in the 21st century. We feel all natural history observations are worth credence, and previous commentaries have highlighted that only a third of all bird species are well known (Xiao et al 2016). However, specifically, we argue that those observations which are placed in the context of a rapidly altering world are of great significance, i.e the 'unnatural' history of a species, regardless of current baseline information.…”

“…ringing stations, incidental‐based broad‐scale citizen science projects such as eBird) or on the breeding biology of birds (Xiao et al . ), which are also critical to our current understanding of avian populations.…”

“…Importantly, this definition of natural history differs from the myriad of basic, life-history data that are collected on the distribution and timing of avian species (e.g. ringing stations, incidental-based broad-scale citizen science projects such as eBird) or on the breeding biology of birds (Xiao et al 2016), which are also critical to our current understanding of avian populations.…”

“…We feel all natural history observations are worth credence, and previous commentaries have highlighted that only a third of all bird species are well known (Xiao et al . ). However, specifically, we argue that those observations which are placed in the context of a rapidly altering world are of great significance, i.e the ‘unnatural’ history of a species, regardless of current baseline information.…”

Nest survival in year‐round breeding tropical red‐capped larks Calandrella cinerea increases with higher nest abundance but decreases with higher invertebrate availability and rainfall

“…To better understand the factors determining nest survival in the tropics, we exploited the opportunity to tease apart the effects of population-level breeding activity and environmental conditions on a year-round breeding bird, the redcapped lark Calandrellla cinerea, in the understudied region of equatorial Africa (Xiao et al 2017). Red-capped larks are ground-breeding open-cup nesters that experience high rates of nest predation, like many lark species (Tieleman et al 2008, Praus et al 2014, Ndithia et al 2017a.…”