So, this is called a "haystache."
It is a bunny nesting behavior, a way to collect hay to make a nest. Rosa thinks she's expecting (it is Mother's Day, after all). My other alert to the state of Rosa's hormones was that when I checked them this morning, there was a huge amount of matted fur in the corner of the cage (a big waste, to a spinner!)
This all is the result of sister bunny (that would be Blanca, "the quiet one") mounting her unsuspecting sister, Rosa, two weeks ago. Blanca probably did this to establish her dominance. The mounting behavior then tricks the victimized Rosa into a series of hormonal events called "pseudopregnancy," ie ovulation. Too bad, as I would love at some point to have some kits! A few minutes after I got the haystache photo, Rosa dropped the hay and decided to eat it. A much better use!
On the knitting front, I completed a sweater for cousins who just had a baby girl. The pattern is "Helena" from Knitty. Done in some leftover Knitpicks Brava Worsted. I ran low on yarn and rather do the ties I did some button holes and added buttons.