At least five members of Twitter’s Cortex artificial intelligence group 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.

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 technology companies and universities to bolster their AI capabilities.

Twitter declined to comment.

Update on December 21: Minh Tran, an “AI Curator” at Twitter Cortex, has also left, according to a tweet.

Update on March 28: Clément Farabet‏, a cofounder of Madbits, which Twitter acquired in 2014, announced in a tweet earlier this month that he has left Twitter Cortex and joined Nvidia. He’s now Nvidia’s vice president of AI infrastructure.