At least five members of Twitter’s Cortex artificial intelligence group (AI) have left this month at a time when companies are rushing to accumulate AI talent.

Earlier today Kevin Swersky tweeted out a photo of his laptop and Twitter badge indicating his departure.

Goodbye @TwitterBoston #TwitterCortex! Thank you for all of the wonderful memories! pic.twitter.com/0XzHed3XRi

— Kevin Swersky (@kswersk) November 23, 2016

Two days earlier, Jasper Snoek and Alex Wiltschko had done the same thing.

https://twitter.com/awiltsch/status/800799774773362688/

It has been fun! I will miss you @TwitterBoston #TwitterCortex. On to the next adventure! pic.twitter.com/FLjnZ8SfIL

— Jasper (@latentjasper) November 21, 2016

On Monday Google announced that a key member of the Twitter Cortex team, Hugo Larochelle, had been selected to head up the company’s new artificial intelligence and deep learning division in Montreal. Larochelle shared his badge and MacBook photo on November 11.

Thanks everyone at #TwitterCortex and @TwitterBoston , I'll miss you all! Now to the next challenge. pic.twitter.com/qjTnuIXVpJ

— Hugo Larochelle (@hugo_larochelle) November 11, 2016

And Ryan Adams did that, too, on the same day.

On to new adventures pic.twitter.com/esH2qgnVc5

— Ryan Adams (@ryan_p_adams) November 11, 2016

All five joined Twitter following the social networking company’s acquisition of startup Whetlab in 2015.

More recently Twitter acquired AI startup Magic Pony.

Apple, Amazon, Facebook, Google, and Microsoft have all been hiring people from other technologies and universities to bolster their AI capabilities. Some companies conduct more academic research than others.

Twitter did not immediately respond to a request for comment.

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