The Slaty Flowerpiercer, known scientifically as Diglossa plumbea, is a diminutive passerine bird, a resident of the Talamancan montane forests. This species exhibits sexual dimorphism. The adult male is adorned in blue-grey plumage with a lead-grey throat and breast, while the tail and wings are a darker blackish hue, softened by grey feather edges. The female, on the other hand, is cloaked in olive-brown above, with a paler throat and breast that gently transitions to buff on the belly. Juveniles resemble the female but are distinguished by two tawny wing bars and faintly streaked buff-yellow underparts.
When identifying the Slaty Flowerpiercer, look for its unique upturned bill with a hooked upper mandible and pointed lower mandible, a feature that is quite distinctive. The bird measures a mere 10 cm in length and tips the scales at approximately 9 grams.
This bird is commonly found in the canopy and edges of mountain forests, thriving in sunlit clearings and areas abundant with flowering shrubs. It is also known to frequent gardens.
The Slaty Flowerpiercer's breeding range extends from 1200 meters in elevation in the northern reaches of Costa Rica to 1900 meters in the southern mountains. It can also be found well above the timberline in páramo habitats.
This species is known for its interactions with territorial hummingbirds. When confronted by these feisty competitors, the Slaty Flowerpiercer often retreats to dense cover to avoid conflict.
The Slaty Flowerpiercer communicates with a thin 'tsip' call. The male's song is a complex symphony of whistles, warbles, and trilled notes, which can be phonetically rendered as "see-chew see-chew see-chew seer seer surrzeep, tsee tsew tsink tsink tsink."
The female Slaty Flowerpiercer is solely responsible for constructing the large cup nest, which is made of coarse plant material and lined with fine fibers. The nest is strategically placed within a dense shrub, grass tussock, or pine, anywhere from 0.4 to 4 meters above the ground. The clutch consists of two brown-speckled pale blue eggs, which the female incubates alone for a period of 12 to 14 days until they hatch.
True to its name, the Slaty Flowerpiercer feeds by piercing the base of flowers to extract nectar with its brush-like tongue. It also supplements its diet with tiny insects, which it captures from foliage or in mid-flight.
The Slaty Flowerpiercer is currently classified as Least Concern on the IUCN Red List, indicating that it is not at immediate risk of widespread decline.