(just about all facts from Monash Uni Malaysia 2016 Study: Alien origins of the Common House Crow) Great research and clearly written.
Crows are the Creme de la Creme of feathered Scavengers. In this case – Corvus splendens, the Asian House Crow. Everyone else on the Scavenger tree in the urban environment will never match their skill set. They are the outright Specialists. “Rats of the Air” comes to mind. (Am sure someone else coined that expression but I refuse to google it). They are 99.2% black (my statistic), apart from those quite freaky brown-black eyes and in the right light, shimmery grey through the neck area.
This bird has been almost forever common throughout all Countries fronting onto the Bay of Bengal. Much trade over many years between Malaysia and the rest around the Big Bay. Birds love flying downwind as there is more fun and less effort required. Peninsular Malaysia, in meteorological terms is ‘downwind of those Countries around the Bay of Bengal.
History is that in the 1890’s more than a few House Crow were imported from Sri Lanka to Port Klang on the Peninsular west coast to control a plague of Caterpillars. Port Klang is at the mouth of Sungai Klang (river) which flows from the foothills behind KL. The Record book shows 56 House Crows being delivered on consignment. This movement of Crows from one Country to another begs the question: Was that a girls and boys mix or mainly lopsided boys or girls? At that time, Crows had been established for some years throughout Johor and Singapore, more than likely arriving by clandestine boat passage. Back in the 1880’s it was sufficient land distance from Johor to KL, for Crows to not become Rats of the Air as they are today in KL. That consignment at Port Klang changed everything.
No doubt Crow/s loved the gourmet Caterpillar feast, and thought it most splendid. What do you do during and after any feast? You cavort, in my case hopefully with people of the opposite sex (These days? Strictly with my wife who is a great cavorter herself). Consider Humans vs Crows: not much difference when things come down to it. What happens during and after that bountiful feast? Boy Crow falls in love and lust with Girl Crow resulting in many babies being made. The Crows stayed in love. Downstream wafts and rubbish rafts from up-stream (Sungai Klang) in KL were too much to ignore. They moved with the humans who were finding their own trail seeking work and bigger bucks in the rapidly expanding Kuala Lumpur. Invasion complete.

!LATE BREAKING NEWS!
Just now! I overheard a small part of a quiet but ernest and nervous story that there maybe a Crow HQ/Temple in Cheras, somewhere. Quite odd and slightly strange events in the general area have reportedly increased over time. Apparently stats show that Motor Vehicles have a higher breakdown rate than anywhere else in KL. Increasing incidences reported of house windows randomly shattering in the general area of the suspected HQ/Temple. Residents described this odd, uncomfortable but persistent sound for some minutes leading up to the Windows shattering. The sound was almost insubstantial, but could be felt in their gut region to the point of nausea. When pressed to describe it, almost all residents likened the sound to – “as many finger scrapes across the blackboard that is possible at once”.
The location of Crow Central is vaguely described as: having the appearance of a large tree stump in a stinking and rotting swamp. Shouldn’t be too hard to find! But, it is Cheras. Nothing is confirmed yet and am not convinced that the story is true. The story teller is a respectful honest person who has been many times the sceptic in the past. Now?
Could the Crows be responsible for the Cheras Tug effect? Maybe the fabled Crow Beak Scrape Pyramid has been in action at the Temple Altar affecting nearby time and space? Windows shattering? Makes a Sceptic ask questions. Maybe it’s a backroom Crow Crew out the back of a somewhere tree in Cheras sucking up all the bandwidth running logistics for the Crows’ suburban raiding run? It seems only Crows will know the entire truth of that.