"As a student of English linguistics, I can explain this phonological phenomenon quite thoroughly - it is called linking and it causes the speaker to link the words ending in a consonant with words beginning in a vowel - in this case the normally unstressed "D" sound at the end of "find" gets linked with the schwa sound standing for the indefinite article "a" in fluid speech and together they create a sound which is one of the ways of pronouncing the definite article "the" in English. I hope that explains it :-)"

Kudos for that. I myself am a TEFL teacher, graduated in linguistics. And now for 'linking-"R"'s :)