Theristicus caerulescens
Silhouette: Robert Cooke · PhyloPic
In 3 days ~20% in a week ~40%
The plumbeous ibis (Theristicus caerulescens), also formerly called the blue ibis, is a large distinctive ibis species endemic to parts of central South America. The plumbeous ibis has historically undergone frequent reclassification and been placed in various genera such as Molydophanes, Geronticus, Theresticus and Harpiprion. It has also been referred to as Ibis caerulescens and Theresticus (Harpiprion) caerulescens. Nevertheless, this ibis has traditionally been assigned to the monotypic genus Harpiprion, carrying the binomial name Harpiprion caerulescens; on the basis that this species was previously believed to have no close relatives. However, phylogenetic analyses based on both nuclear and mitochondrial DNA markers have suggested that the plumbeous ibis is closely related to other ibis species in the genus Theresticus such as the buff-necked ibis; given the markedly low genetic distances between the plumbeous ibis and other Theresticus species. Hence, the current placement of the plumbeous ibis in the genus Theresticus appears justified.
This large ibis measures 71–77 cm in length, with a wing length of 397-450mm... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Parque Estadual Encontro das Águas | 🇧🇷 Brazil | |
| 2 | El Impenetrable National Park | 🇦🇷 Argentina | |
| 3 | Iberá National Park | 🇦🇷 Argentina |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Santa Cruz de la Sierra | 🇧🇴 Bolivia |
With luck
About 10% of wildlife watchers report a Plumbeous Ibis sighting in Iberá National Park on a given day, based on 118 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 174th most-seen of the 284 birds we can rate there. Over three days the chance rises to about 20%, and over a week to about 40%, if each day is a fresh chance.
August
In that month about 20% of wildlife watchers report a Plumbeous Ibis in Iberá National Park on a given day, against under 5% in June and October–December, the lowest months.
Between 9 am and noon
Across all the parks we cover, that three-hour window holds the most Plumbeous Ibis sightings with a recorded time, and about 8 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
3rd of 3
Of the 3 parks where we can rate Plumbeous Ibis sightings, Iberá National Park ranks 3rd at about 10%. The best odds are in Parque Estadual Encontro das Águas (Brazil, about 30%) and El Impenetrable National Park (Argentina, about 20%).
GBIF citizen-science records
It is estimated from how often the Plumbeous Ibis is recorded against all the birds logged in Iberá National Park (118 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
