Having (finally) got to look at the LBJs book... I doubt there's a particular reason to think these (seemingly two birds in the photos) might be Nicholson's pipit ( = long-billed pipit), but, compared to that species, they seem more likely to be African pipit:
- Pale on undertail (I doubt it's safe in these photos to call it white rather than the alternative of 'buffy-white') is extensive on inner web of outermost feather (much less on Nicholson's pipit).
- Dense narrow chest-band of streaks rather than wider and sparser on Nicholson's pipit. (Macaulay photos of Nicholson's pipit show all manner of chest-patterns including African-pipit-like; given what we know Macaulay to be like, misidentifications must be rife indeed among their pipits in Africa.)
(The LBJs book leaves regular field guides dead in the water, to put it mildly - assuming, of course, that the stuff in it is right.)