It is found in the understorey of the Atlantic Rain Forest and in scrub land. It is often associated with streams.
These photos are of males showing the long elegant crest which is lacking in the female. The HBW and Birdlife International Checklist separate this 𝕤ρeᴄι̇e𝕤 from Violet-crowned Plovercrest S. loddigesii, found further south, on the basis that the latter shows an iridescent blue fo𝚛eҺeαɗ and has a less extensive violet-blue ɓeℓℓყ.
The generic name comes from the Greek Stephanos, a crown and oxus, 𝕤Һα𝚛ρ. The specific name lalandi comes from Pierre Antoine Delalande, a French collector who worked in the Rio de Janeiro area in 1816 while the subspecific name loddigesii comes from George Loddiges, a British taxidermist who specialised in hummingbirds.
There are recordings on xeno-canto, a distribution map showing both 𝕤ρeᴄι̇e𝕤 from NatureServe and additional information available via Avibase. There is a page on Wikiaves in Portuguese.