It's difficult to be sure.
Wilfrid Scawen Blunt was an Englishman who travelled extensively in the Middle East, spending many years in Egypt but also seeing other Arabic speaking countries such as Algeria and Syria. He was known as a poet and a translator of Arabic poetry. In particular, he worked together with his wife Anne Blunt on translations from Arabic of works such as the Muʻallaqāt which they translated as The Seven Golden Odes of Pagan Arabia. In this project, apparently it was Lady Anne who did the language translation and Wilfrid who turned it into English verse.
Evidence in favour
- The Morgan Libary in the USA has a manuscript of "The Camel Rider", which is listed as "translated from the Arabic by Wilfrid Scawen Blunt". However, this could be a cataloguing error - the manuscript is not written by Blunt, and dates to several years after the poem's publication, so the scribe (Ethel M. Offer) might have just copied "From the Arabic" from the original.
- In his collected works, the poem "The Camel Rider" is included in the section "From the Arabic", suggesting that the poems are translated rather than written himself from scratch. However, the next point below provides a counterpoint to this.
In Alfred H. Miles, The Poets and the Poetry of the Century, he draws the conclusion that Blunt's poems "From the Arabic" were in fact his own work:
Regarding Mr. Blunt's work apart from its great interest as marginalia, his best things, since certain of the "Love-Sonnets," are perhaps the poems "From the Arabic," - presumably as Mrs. Browning's sonnets were "From the Portuguese," and "Sed Nos Qui Vivimus," both contained in the "New Pilgrimage" volume. Mr. Blunt presents these as experiments in assonance, and as such he is well-justified of them, for though hardly an entire success, they come very near being so.
(Browning's Sonnets from the Portuguese were indeed written by herself.) However, Miles doesn't justify this claim, making it only with the weasel word "presumably".
In the PhD thesis "The Literary Achievement of Wilfrid Scawen Blunt" by Mohammed Tawfiq Muhieddin el Bujairami, a Syrian who studied at Sheffield University, he analyses Blunt's success in capturing the style of Arabic poetry even without exact translations:
Blunt succeeded in capturing the spirit of these desert songs [actual Arabic songs translated by his wife] and reproducing their melodious effect through assonance. In a series of rich, evocative images, he recreates the desert atmosphere, of which he had first-hand knowledge, and many lines hark back to his travels in Arabia. The images in stanzas IX, X and XI of "The Camel Rider", for example, are recollections of the features of the Euphrates Valley. The references to the valley of Thyme, to Saba, and to hearth stones are contrived to convey suggestive associations; such references are recurrent in ancient Arabic love poetry. [...]
These lines, it must be noted, [lines quoted from "The Camel Rider"] are imitations and not translations of any Arabic text. Blunt penetrates and captures the spirit of the Arabic tradition; in contrast, Sir William Jones's "Solaima" depends for its "Arabian" qualities on various Arabic names that occur in it, and it appears stilted in comparison. [...]
Another element which Blunt captures in his Arabic imitations is the undercurrent of warm emotion, felt even by the natural objects, which do not act as a merely passive, inanimate background, but also sympathize with the singer in his suffering. The wind, the sand, the stars and the camel become active participants in the human drama, as can be seen in stanzas III, IV, V and VI of "The Camel Rider".
el Bujairami says directly that "The Camel Rider" is an imitation and not a translation of any Arabic text - suggesting that not only is it not a direct translation, it's also not even based on any one particular text. This is probably the most compelling piece of evidence - as well as being a scholar writing his PhD specifically on Blunt, el Bujairami was also (presumably) a native speaker of Arabic himself, and thus in a good position to conduct a proper search for an original Arabic poem which Blunt might have translated.
In all the sources I've checked, nobody has identified an original song in Arabic which Blunt was reproducing. However, given that Blunt spent years living and travelling in Arabic countries, there remains the possibility that he heard it somewhere and remembered it, even that it's never been recorded in writing and thus wouldn't show up even in el Bujairami's searches.
Discussion on translation
Translating stories in general requires more than just literally translating the words. This is especially true for poetry, and even more especially for translations between languages such as Arabic and English which have such different structures and literary stylistic forms. Translating poetry can be almost like writing new poetry: you need to decide which writing technique in the target language can most accurately capture the effect of an untranslatable technique in the source language.
For this reason, the use of the term "imitation" is not, in itself, definitive proof that Blunt's poems "From the Arabic" were not translations of any pre-existing Arabic work. Let's compare the above with descriptions of The Seven Golden Odes of Pagan Arabia which was definitely a translation of an existing work: it's described as a "fine and original, though somewhat free, rendering into English verse", and el Bujairami mentions in the same thesis that in this translation Blunt "succeeded in producing, in English rhythm, the sound effects and the real atmosphere of the originals". It seems that his translations in general were more concerned with effect and atmosphere than literal meaning.
el Bujairami makes mention in general of Blunt's "imitations and translations", suggesting that these are two different things. But, as Peter Shor notes in a comment, there is a continuum between the two, with "a very free translation" somewhere in the middle. el Bujairami also says that:
In the Arabic song, which is usually meant to be heard over long distances when chanted, the long vowels (which Blunt tries to reproduce in his English imitation) impart a plaintive echo to the song, reflecting the yearnings of the soul of the Bedouin lover.
It's not clear from the context whether "the Arabic song" here refers to a specific Arabic song which was translated/imitated in "The Camel Rider" (this passage comes only a few paragraphs after several verses of "The Camel Rider" are quoted) or whether it means Arabic songs in general.
Another difficulty in the process of imitation is the technical difference between English and Arabic measures. The latter are quantitative, rather like the classical Greek and Latin measures. To the four principal meters of English verse, Arabic poetry can be moulded in sixteen different prosodic measures. In his effort to reproduce its forceful rhythms, Blunt resorted to recurrent spondees in a number of lines.
Again this paragraph is illustrated with a verse from "The Camel Rider". Does this mean Blunt was reproducing the rhythms of a particular Arabic poem, or simply reproducing the style of Arabic poetry in general?
Summary: I think there are two possibilities for the answer to your question.
- Blunt started from a particular Arabic song and made a very "free" translation, prioritising the preservation of Arabic style and rhythm over that of literal meaning.
- Blunt wrote "The Camel Rider" himself, but with knowledge of many Arabic songs he'd heard, trying to capture their general style and atmosphere.
2 is probably the more likely option, but I don't think we have quite enough evidence to rule out 1, especially given we know that's what he did with other Arabic-to-English translations.