I first encountered Meinertzhagen in an entertaining passage in Bill Bryson's excellent book 'A Short History of Nearly Everything', detailing the consternation at the Natural History Museum when they opened the crates of bird specimens left to them by Meinertzhagen and discovered the museum's own labels on most of the contents. This, Bryson notes "explained his habit of wearing a large overcoat even in warm weather".
I have also come across quotes from him in various accounts of the campaign in East Africa in WWI, throughout which he appears to have sat on a deckchair behind the lines smoking a pipe and criticising his superiors - a dream job for most of us, I suspect.
There is an outstanding Wikipedia biography, from which the following quotes come:
Colonel Richard Henry Meinertzhagen CBE DSO (March 3, 1878 - June 17, 1967) was a British soldier, intelligence officer, ornithologist and expert on bird lice. He was influential in life and had a legendary reputation for his exploits around the world. Studies on his work on birds and historic notes after his death however raised serious questions on his integrity and have made him a controversial character.
In East Africa in 1905, he crushed a major revolt by killing the Orkoiyot (spiritual leader) who led it. He collected some of the tribal artefacts after this revolt. Some of these artefacts, including a walking stick and baton belonging to the Nandi tribal leader Koitalel arap Samoei, were returned to Kenya in 2006.
His unpublished diaries hint at a successful rescue attempt of one of the Russian Grand Duchesses, possibly Tatiana
Tom Segev considers that Meinertzhagen was "at once a great antisemite and a great Zionist". He justifies this analysis by this excerpt from Meinertzhagen's Middle East Diary : "I am imbued with antisemitic feelings. It was indeed an accursed day that allowed Jews and not Christians to introduce to the world the principles of Zionism and that allowed Jewish brains and Jewish money to carry them out, almost unhelped by Christians save a handful of enthusiasts in England".
He was a prolific diarist and published four books based on his diaries, which make fascinating and often insightful reading. However, his Middle East Diary (1959) contains dozens of entries that are probably fictional, including those on T. E. Lawrence and on Hitler. Meinertzhagen's claimed to have mocked Hitler by giving a Heil Meinertzhagen salute in response to those given by the men around Hitler. He also claimed to have carried a loaded gun in his coat pocket at a meeting with Hitler and von Ribbentrop in July 1939 and was "seriously troubled" about not shooting when he had the chance, adding "If this war breaks out, as I feel sure it will, then I shall feel very much to blame for not killing these two." Lockman in his book shows that Meinertzhagen later falsified his entries on T. E. Lawrence. The original diaries kept in the Rhodes House Library contain differences in the paper used for certain entries as well as in the typewriter ribbon used, and there are oddities in the page numbering.
"Meinertzhagen knew no half measures. He was logical, an idealist of the deepest, and so possessed by his convictions that he was willing to harness evil to the chariot of good. He was a strategist, a geographer, and a silent laughing masterful man; who took as blithe a pleasure in deceiving his enemy (or his friend) by some unscrupulous jest, as in spattering the brains of a cornered mob of Germans one by one with his African knob-kerri. His instincts were abetted by an immensely powerful body and a savage brain..."
– T. E. Lawrence, Seven Pillars of Wisdom, 1926
Note the equating of the beating to death of unarmed POWs with "an unscrupulous jest".
While in India he killed one of his personal assistants in a fit of rage and had the local police officer cover it up as a death due to plague...
Gavin Maxwell wrote about how his parents would scare him and other children to behave themselves when Meinertzhagen visited with "...remember...he has killed people with his bare hands..."
Meinertzhagen's second wife, the ornithologist Anne Constance Jackson, died in 1928 at age 40 in a remote Scottish village in an incident that was ruled a shooting accident. The official finding was that she accidentally shot herself in the head with a revolver during target practice alone with Richard.
That has to be the most magnificently colonelesque inquest verdict ever...