Synallaxis brachyura
Silhouette: Sheatherius · PhyloPic
In 3 days ~10% in a week ~20%
The slaty spinetail or slaty castlebuilder, (Synallaxis brachyura), is a passerine bird in the Furnariinae subfamily of the ovenbird family Furnariidae. It is found from Honduras south to Peru. The slaty spinetail has four subspecies:
The sexes have the same plumage. Adults of the nominate subspecies S. b. brachyura have a grayish supercilium on an otherwise darker gray face. Their crown and nape are deep rufous-chestnut, their back is dark sooty brown to slate-brown, and their rump and uppertail coverts are slightly browner than the back. Their wing coverts and base of their flight feathers are deep rufous-chestnut and the rest of the flight feathers are dark brown. Their tail is the same brown as the rump and uppertail coverts; it is long and the feathers lack barbs at their tips, giving a spiny appearance. Their throat is blackish, their breast and sides dark sooty brown, their belly a paler and grayer brown, and... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Tenorio Volcano National Park | 🇨🇷 Costa Rica | |
| 2 | Machalilla National Park | 🇪🇨 Ecuador | |
| 3 | Chirripó National Park | 🇨🇷 Costa Rica | |
| 4 | La Amistad International Park (Panama) | 🇵🇦 Panama | |
| 5 | Piedras Blancas National Park | 🇨🇷 Costa Rica | |
| 6 | Arenal Volcano National Park | 🇨🇷 Costa Rica | |
| 7 | Darién National Park | 🇵🇦 Panama | |
| 8 | Gandoca-Manzanillo Wildlife Refuge | 🇨🇷 Costa Rica | |
| 9 | Tapantí-Macizo de la Muerte National Park | 🇨🇷 Costa Rica | |
| 10 | Farallones de Cali National Natural Park | 🇨🇴 Colombia | |
| 11 | Corcovado National Park | 🇨🇷 Costa Rica | |
| 12 | Braulio Carrillo National Park | 🇨🇷 Costa Rica | |
| 13 | Tortuguero National Park | 🇨🇷 Costa Rica | |
| 14 | Volcán Barú National Park | 🇵🇦 Panama | |
| 15 | Manuel Antonio National Park | 🇨🇷 Costa Rica | |
| 16 | Los Nevados National Natural Park | 🇨🇴 Colombia | |
| 17 | Carara National Park | 🇨🇷 Costa Rica |
Rare
Under 5% of wildlife watchers report a Slaty Spinetail sighting in Arenal Volcano National Park on a given day, based on 389 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 249th most-seen of the 503 birds we can rate there. Over three days the chance rises to about 10%, and over a week to about 20%, if each day is a fresh chance.
September and October
In those months about 10% of wildlife watchers report a Slaty Spinetail in Arenal Volcano National Park on a given day, against under 5% in November to August, the lowest months.
Between 6 and 9 am
Across all the parks we cover, that three-hour window holds the most Slaty Spinetail sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
6th of 17
Of the 17 parks where we can rate Slaty Spinetail sightings, Arenal Volcano National Park ranks 6th at under 5%. The best odds are in Tenorio Volcano National Park (Costa Rica, about 10%), Machalilla National Park (Ecuador, about 10%) and Chirripó National Park (Costa Rica, under 5%).
Same family: Furnariidae
The closest relatives of the Slaty Spinetail that you can see in Arenal Volcano National Park (family Furnariidae, Ovenbirds and Woodcreepers) are Wedge-billed Woodcreeper (about 30%), Streak-headed Woodcreeper (about 20%) and Spotted Woodcreeper (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Slaty Spinetail is recorded against all the birds logged in Arenal Volcano National Park (389 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.
