Episode 4 of the David Tennant narrated Earthflight (about South America) received 3.91million viewers on BBC One.
The final figures (and those for BBC HD) will be announced in about 10 days but this compares to the overnight (not final) figures for episodes 1 to 3 of 5.12m (during Christmas week), 4,63m and 4.13m respectively.
At 8pm Earthflight unfortunately was scheduled against Emmerdale and the Coronation Street on ITV1 so it is a tough slot. For example on BBC Two in that slot was a documentary called Edward VII: Prince of Pleasure which only received 1.63m viewers.
Now that the series is into its fourth week it was also not promoted by the BBC this week.
