While I was in Tonga this year, I documented a female humpback whale that had calfs in 2008 and 2009, meaning she had calfs two years in a row, and visited Vava'u two years in a row.
The female humpback (whom we named Lilo) is the mother of Scratches (calf #1/ 2008) and Stitches (calf #4/ 2009) (details here).
Thanks to help from two people (Nonie Silver and Karen Stone), there is a second example of this!
Here is a photograph of Chibi-chan (calf #16/ 2008) and mom, which I took on 12 September 2008:
As is apparent from this image, the adult whale has an easily identifiable pattern on her body.
Karen Stone sent me images of this same female with a calf earlier this month, making this calf #29 for 2009. Karen named the calf "Floppy" for its penchant for flopping around on its mother's head and back.
Subsequently, sharp-eyed Nonie Silver, who also photographed this whale with a calf this season, found the match to Chibi-chan's mother in my 2008 file.
Scratches (calf #1/ 2008) and Stitches (calf #4/ 2009) have the same mom.
Chibi-chan (calf #16/ 2008) and Floppy (calf #29/ 2009) have the same mom.
Amazing what we can learn with a bit of hard work and cooperation. Thank you Nonie and Karen!