Comparative reproductive ecology of Old and New World Trogons, an order in decline across the world

• Published in: Ecology and evolution 2024-04, Vol.14 (4), p.e11273-n/a
• Main Authors: Şahin Arslan, Necmiye, Martin, Thomas E.
• Format: Article
• Language: English
• Subjects: Animal reproduction; Anniversaries; Behavioural Ecology; Borneo; Breeding success; Conservation Ecology; Demography; Ecology; Families & family life; Harpactes whiteheadi; Life history; Life History Ecology; life history traits; National parks; nestling growth; parental behavior; Population; Population decline; Predation; Reproduction; Trends; Trogon; Trogon collaris; Trogon personatus; tropics; Venezuela; wing development
• ISSN: 2045-7758; 2045-7758
• DOI: 10.1002/ece3.11273

Many tropical species show declining populations. The pantropical order Trogoniformes has 76% of its species ranked as declining, reflecting a worldwide problem. Here, we report on the reproductive ecology and life history traits of the declining and near‐threatened old world Whitehead's Trogon (Harpactes whiteheadi), the declining new world Collared Trogon (Trogon collaris), and the stable Masked Trogon (T. personatus). We also reviewed the literature on reproductive ecology and life history traits of trogons to assess possible commonalities that might help explain population declines. We found that the declining Whitehead's and Collared Trogons had reasonable nest success (32% and 25%, respectively), while the stable Masked Trogon had poor reproductive success (9%), all contrary to population trends. However, the limited literature data suggested that poor reproductive success may be common among trogons, which may contribute to population declines. Parents fed young at a low rate and had long on‐bouts for incubation and nestling warming that reduced activity at the nest, as favored by high nest predation risk over evolutionary time. We found that young fledged from the nest with poorly developed wings, as also favored by high nest predation risk. Evolved nestling periods among trogon species suggests that poor wing development is likely common. Wing development has been shown to affect juvenile survival after leaving the nest. The poor wing development may be an important contributor to population declines that deserves more attention. Evolved life history traits are important to recognize as creating population vulnerabilities in a changing world. We examine the avian order Trogoniformes, which has 76% of its species classified as declining and assess possible reasons for such worldwide declines. We provide field data on breeding biology and life history for three species and review the literature for the order. We provide possible reasons for population declines based on nesting success and a novel argument based on developmental state at fledging that affects juvenile survival.