Why do large eagles and vultures produce relatively few young each year?

Large eagles and vultures produce relatively few young each year due to a combination of biological and ecological factors. These species often have long breeding cycles; for instance, some large eagles and condors require over 15 months to complete the breeding period, and some species, such as the crowned eagle, normally breed only every second year.1

The low reproductive rate is also influenced by the high costs of parental care. Because these birds invest significant time and energy into rearing their young—including long incubation periods and extended postfledging dependency—they have limited capacity for frequent reproduction. Furthermore, breeding success is often constrained by environmental factors, such as poor food supplies, adverse weather, or territorial behaviour in crowded habitats, which can lead to lower success rates in tropical regions compared to temperate zones. Consequently, while small falcons may rear 2.5 to 3 young per year, some large eagles and vultures may successfully rear 0.4 or fewer young per pair annually.12