Serpophaga griseicapilla
Silhouette: Emily Willoughby · PhyloPic
In 3 days ~70% in a week ~90%
Straneck's tyrannulet (Serpophaga griseicapilla), also known as the monte tyrannulet and grey-crowned tyrannulet, is a small species of bird in the family Tyrannidae, the tyrant flycatchers. It is found in Argentina, Bolivia, Brazil, Paraguay, and Uruguay.
Straneck's tyrannulet has a confusing taxonomic history. It had been known since the 1990s by the binomial Serpophaga griseiceps, which had previously been assigned to specimens that were later recognized as immatures of what was then the white-bellied tyrannulet (Serpophaga munda) and so was invalid. Roberto Straneck formally described the species and assigned its current binomial in 2007. It was later given its English name in his honor.
Straneck's tyrannulet is monotypic. Straneck's tyrannulet is 9 to 11 cm (3.5 to 4.3 in) long and weighs 4.4 to 7.5 g (0.16 to 0.26 oz). The sexes have the same plumage. Adults have a gray crown and nape with a hidden bit of white on some black central crown feathers. They have a thin white supercilium, a white crescent under the eye, and a dark gray line through the eye on an otherwise grayish white face. Their upperparts are olivaceous brown. Their... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | El Impenetrable National Park | 🇦🇷 Argentina | |
| 2 | El Palmar National Park | 🇦🇷 Argentina | |
| 3 | Península Valdés | 🇦🇷 Argentina | |
| 4 | Amboró National Park | 🇧🇴 Bolivia | |
| 5 | Iberá National Park | 🇦🇷 Argentina |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Rosario | 🇦🇷 Argentina | |
| 2 | Cordoba | 🇦🇷 Argentina | |
| 3 | Buenos Aires | 🇦🇷 Argentina | |
| 4 | Santa Cruz de la Sierra | 🇧🇴 Bolivia | |
| 5 | Asuncion | 🇵🇾 Paraguay | |
| 6 | Montevideo | 🇺🇾 Uruguay |
Possible
About 30% of wildlife watchers report a Straneck's Tyrannulet sighting in El Impenetrable National Park on a given day, based on 106 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 51st most-seen of the 219 birds we can rate there. Over three days the chance rises to about 70%, and over a week to about 90%, if each day is a fresh chance.
June
In that month about 60% of wildlife watchers report a Straneck's Tyrannulet in El Impenetrable National Park on a given day, against about 10% in February, the lowest month. That is one of El Impenetrable National Park's driest months, with about 35 mm of rain against 120 mm in March. December has too few records to rate.
Between 9 am and noon
Across all the parks we cover, that three-hour window holds the most Straneck's Tyrannulet sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Yes
Of the 5 parks where we can rate Straneck's Tyrannulet sightings, El Impenetrable National Park has the highest daily chance: about 30%. Next come El Palmar National Park (Argentina, under 5%) and Península Valdés (Argentina, under 5%).
GBIF citizen-science records
It is estimated from how often the Straneck's Tyrannulet is recorded against all the birds logged in El Impenetrable National Park (106 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.
