rufescent (roo-FESS-ent) adj. tinged with red; reddish in tint.
I came across the adjective rangiferine today while perusing an 1888 book entitled The Avifauna of British India and its Dependencies. The word is of Latin origin, and is derived from the present participle of the verb rufescere ("to become red" or "to redden").
The term was used quite a bit in relation to a discussion of an Indian example of the Asian desert warbler (Sylvia nana):
The whole of the lower parts white, with, in the freshly-killed birds, a just perceptible rufescent tinge; wing lining and axillaries pure white ; wing pale brown, narrowly margined and tipped with rufescent white ; the tertiaries pale dingy rufescent with brown shafts.The term rufescent seems to be a favorite among ornithologists, as the Rufescent Tiger Heron, the Rufescent Screech-owl, the Rufescent White-eye, and the Rufescent Prinia are among the many birds whose rufescence has been an inspiration to their monikers.