The History and Population Dynamics of the Scarlet Ibis (Eudocimus ruber) in Southern and Southeastern Brazil

1. Introduction

A flagship American bird, the Scarlet Ibis ranges across northern/eastern South America, with two disjunct populations in Brazil: northern (Pará, Amapá, Maranhão) and southern (São Paulo, Paraná, Santa Catarina; Sick 1997). Brazilian records date to the 16th century, with indigenous feather use documented in São Paulo (Staden 1557) and later accounts of its striking plumage by Cardim (1925) and Gândavo (1576).

2. Historical Distribution

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Santa Catarina: Earliest records from 1712–1763 (southernmost historical sightings; Haro 1990), deemed extinct by 2000 (Naka & Rodrigues 2000).

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Paraná: First referenced in a 1653 illustration of Paranaguá Bay (Straube 2005), with 19th-century specimens and sightings (Natterer, Saint-Hilaire) and early 20th-century coastal records (Martins, Krone).

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São Paulo: Isolated 20th-century sightings (e.g., 1961 São Vicente specimen) preceded broader recovery.

3. Population Recovery (1980s–Present)

Recovery began in coastal São Paulo: initial sightings near Santos (1980s), confirmed nesting in Cubatão (1989), and population growth to 385 individuals in Santos mangroves (1998; Olmos & Silva-Silva 2001). By the 2000s, the species expanded to Cananéia (971 foraging individuals in 2009) and established a breeding colony on Ilha do Cardoso (1,000 birds in 2015).

Parallel recoveries occurred in Paraná (Paranaguá estuarine complex, max. 225 individuals by 2013) and Santa Catarina (Babitonga Bay breeding colony, 2011). Dispersal along the coast (evidenced by ringed birds) maintains gene flow between subpopulations (Grose 2016).

4. Drivers of Decline and Recovery

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Decline: Mangrove degradation, hunting for plumage, egg collection (Lago-Paiva 1994), and reduced observer coverage. Isolated groups may have dispersed to remote mangroves (supported by 1781 protection edicts; Straube 2011).

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Recovery: Reduced anthropogenic pressure, habitat tolerance (even in disturbed urban areas), and potential north-south dispersal or historical coastal connectivity (genetic similarity supports both hypotheses; Gonçalves et al. 2010). The 1967–69 introduction of 19 northern pairs to Cubatão (Olmos 2003) may have aided recovery.

5. Conclusion

The Scarlet Ibis’ apparent "extinction" in southern Brazil reflects both anthropogenic impacts and ecological traits (dispersal, habitat preference for dense mangroves). Its recovery highlights the species’ resilience, though estuarine conservation remains critical. Tolerance of moderate human disturbance underscores the value of balancing habitat protection with community coexistence.