My RSPB day job has been so busy this spring that I thought I'd treat myself to a few days away enjoying the natural wonders of Spain.

(For those that don't know, I'm an RSPB Project Manager, and I timed my holiday to be just after the public Consultation had closed in which we are trying to convince Medway Council not to build 5,000 houses on the UK's best site for Nightingales. I know, it's unbelievable! Little did I know that the Consultation would have to be extended because the Council failed to produce the right paperwork - so if you have yet to send your email letter asking the Council to #SaveLodgeHill, please please do. I'm up to 9,400 responses, I'd like to get to 10,000, and it only takes a few minutes to have your say. You can read about the campaign here or leap straight to the e-action here. The consultation now closes on 18 April, so please do it now!)

Well, in southern Spain the Nightingales were already in and singing, but of course I always have my gardening head on, and so was fascinated to see a whole range of British garden plants growing in the wild - beds of Borage and Honeywort everywhere, growing as arable weeds, both such wonderful flowers for bees.

Plus heathy areas full of Rosemary and Rue and French Lavender and all manner of rockroses (Cistus, Halimium and Helianthemum).

But the abiding image I'm bringing home with me from a garden perspective are the House Martins.

It's a species we're concerned about because of their population declines; it's also one I have a personal affection for because they used to build their cup nests outside my bedroom window when I was a child, and I'd wake to their gorgeously cheerful twittering.

But where I used to have one or two nests outside my window, in the cowboy town of El Rocio where I was staying, the House Martins prefer to live in Martin Megatropolises.

Yes, there was the odd property where it was clear that someone had knocked the nests down, but almost without exception it seemed that people were very happy to tolerate the droppings that gather beneath the nests in favour of the delight that House Martins bring.

And someone else was very happy, too...

Yep, Mr House Sparrow, taking advantage of the abundance of holes.

The House Martins are just starting to arrive back in the UK now, so there's still time to tempt them with a ready-made nest box, fixed under the eaves - they are available from the RSPB online shop here. You'll need someone with a ladder and a head for heights to put them up; just make sure you site them where there is a clear flight path in as House Martins need to swoop up and in to their nestsite.

With numbers falling, don't expect House Martins to move in instantly, but the important thing is knowing that it's there for them. And if a sparrow moves in instead, well, they need homes too!

Oh, and what do we say to the idea of losing the best Nightingale site in Britain?