The online bots behind Vladimir Putin's birthday wishes

When President Vladimir Putin turned 65 on 7 October, he was not short of online well-wishers. But how many were real?
A hashtag which translates as "Happy Birthday President" began trending in early that day in Russia.
One of the most popular tweets using this tag is:
While the tweet was shared more than 800 times, none of those sharing it appear to be Russian speakers. They also seemed to lack the personality of an individual, were often advertising services, and with account information containing frequent typos.
"We are a professional photo servic in Vicoria an on Vancouver Island" (sic) said one. Another described themselves as a "Maria Arts Mrketing Guru" (also sic).
Several also contained sexually explicit content.
Who is @vitischeg?
The @vitischeg profile also raises suspicions. The account was created in 2014 yet all tweets posted prior to 20 September appear to have been deleted. An analysis of the timeline suggests the account has stayed inactive for months at a time.
The bio states that the account holder is named Viktor Petrov-Vodkin - who shares his surname with a prominent Soviet painter. But an analysis by BBC Monitoring, using the social media tool Crimson Hexagon, shows the account previously used the name Viktor Vodkin-Petrov.
While the name Viktor, and the profile picture of a bearded man wearing shades, indicate that the owner of the account is masculine, a now-deleted tweet from 16 September uses the feminine form of a verb to describe how the account owner tried to make a salad.
This is not the first time @vitischeg has wished Vladimir Putin happy birthday. In 2016, the account tweeted the same meme of the bear but with the hashtag #PutinDay. That trending tag, as well as @vitischeg's tweets was reported on by two Kremlin-funded outlets, RT and Sputnik.