Letter from the 5th Earl of Cranbrook to Ronald Angus Macdonald commenting on his draft paper on the Seychelles cave swiftlets. He gave advice on preparing his draft for submission to Ibis

Collocalia||Aerodramus||Hydrochous||Collocaliinae||Collocallini

Letter from the 5th Earl of Cranbrook to Ronald Angus Macdonald with advice on studying the Seychelles cave swiftlets, Aerodramus elaphra. The Earl also asked Macdonald about the suppliers of coloured plastic leg-rings for birds of all sizes

Aerodramus elaphrus||Collocalia esculenta||Apus apus||Cimicidae||Mallophaga||Hippoboscidae

Letter from the 5th Earl of Cranbrook to Roy Andries de Groot on how he got his first job and got involved with research on swiftlets

Letter from the 5th Earl of Cranbrook to S. Marchant commenting on Marchant's comment on his manuscript on the nest of Collocalia v. vanikorensis

Aerodramus vanikorensis||Aerodramus salangana||Aerodramus natunae||Aerodramus bartschi||Aerodramus inquietus||Aerodramus ponapensis||Aerodramus rukensis||Collocalia esculenta

Letter from the 5th Earl of Cranbrook to Stanley Cobb informing him that he was still in Malaysia and he could send his manuscript to him. He also mentioned his (the Earl's) work on echolocating calls of swiftlets

Letter from the 5th Earl of Cranbrook to Terence A. Mordue on swiftlets of Papua/New Guinae

Letter from the 5th Earl of Cranbrook to the Curator of Birds, Field Museum of Natural History, Chicago concerning specimen FMNH 87569 from the museum

Letter from the 5th Earl of Cranbrook to the Curator, Sarawak Museum on excessive removal of guano at Niah Cave

Letter from the 5th Earl of Cranbrook to the Director, Information Services, Kuala Lumpur who was about to move the Survey Department in Mountbatten Road, requesting him to plan the renovation in the Survey Department, in such a way that would not cause swiftlets living it the building to abandon the site. He explained the Survey Department was the only location in the whole Federation that the birds made nests inland

Letter from the 5th Earl of Cranbrook to the District Officer, Telok Anson informing him of his research on swiftlets and if there were any boats going to the Pulau Sembilan islands