About Ramphocelus dimidiatus Lafresnaye, 1837
The crimson-backed tanager (Ramphocelus dimidiatus) is a species of bird in the family Thraupidae. It was first described by French naturalist Frédéric de Lafresnaye in 1837, and is one of nine brightly coloured tanager species in the genus Ramphocelus. Evidence from mitochondrial DNA shows that its closest relative is the masked crimson tanager (R. nigrogularis), and the two species split approximately 800,000 years ago. This species has a nickname in Panama: sangre de toro, which translates to "Blood of the bull". It is native to Colombia, Panama, and Venezuela, and has been introduced to French Polynesia. More specifically, it occurs in northern and western Colombia (south to Chocó, where it is uncommon), the Maracaibo Basin in Venezuela, and across most of Panama, where it ranges west to Chiriquí and Veraguas Provinces, as well as Coiba (where it is abundant) and the Pearl Islands. Its natural habitats are subtropical or tropical moist lowland forests and heavily degraded former forest; it also inhabits scrubland and gardens. Adult crimson-backed tanagers measure around 18 cm (7.1 in) in length. The adult male has a silver sheen on its lower mandible; its entire head and chest are maroon red, shifting to bright red on its lower back and abdomen, while its wings and tail are black. The female is duller in colouration, with blackish underparts. A nest containing a clutch of two blue eggs with fine dark dots has been recorded for this species. One field study testing for blood parasites found that two out of twelve tested individual crimson-backed tanagers carried Plasmodium, and the study concluded that the overall infection rate was low compared to results from similar studies done in other locations.
