Getting The Shot But With a Moral Dilemma

I've been after a decent picture of a Goldcrest for quite awhile. As you may know they are Britain's smallest bird and don't sit still for a second so are a tricky little devil to get a photo of. There's a couple on my local nature reserve and I've even spotted one near the feeders at work but to date nothing to write home about.

At the weekend I was down in London so decided to spend the day at the London Wetland Centre in Barnes. It was a mucky grey day so I wasn't expecting much. I watched two kingfishers getting in the Spring mood but they were a long way away and the parakeets just stayed high in the trees. Half way round I spotted two chaps staring into a conifer and I just knew they'd spotted a Goldcrest. As usual it was flitting around bouncing from branch to branch always out of shot. One of the men then got his phone out and started playing the goldcrests song from an app into the tree. Almost immediately the bird returned and started singing back in response. I snapped away getting easily my best pictures by far but I began to wonder if this was right. Is it any different to putting out feeders to attract in the birds? I'm not sure and I felt slightly guilty, did the bird return thinking there was a potential mate around or was it defending a territory? It's a tricky one.