An Unexpected Dilemma

We got a hanging pot of little flowers a while ago to prettify our balcony a bit. Just yesterday, we discovered that a little bird has decided that it's prime real estate, and has started building a house there!



The picture doesn't show it well, but this little guy was awfully busy this morning working on a nest just below the flower level. It has been a good little tenant so far, and we'd be happy to keep it there! Here's my worry though: I have to water that plant every so often (it's probably due for a drink today, even), but how can I water it without flooding the little bird home out??? Any suggestions?