unexpected lodgers in the greenhouse

Robins are nesting in my greenhouse.  I was watering one day, and stretched out my hand to remove a pile of leaves that seemed to have suddenly collected in a tray of bronze grasses, when I realised it was in fact a bird's nest.  There was no sign of any actual bird, and I assumed that the greenhouse had got too hot for them and that the nest was abandoned, as we'd had a couple of unusually warm and sunny days before I put this year's shading paint on.  I was beginning to think that if I removed it carefully and treated it for fleas my nieces and nephew might like it, when I saw one day that there was an egg in it.  Still no signs of birds, and I again thought it must be abandoned, but left it alone.  A day or two later I saw there was another egg, brownish pink.

My partner, who knows more about birds than I do, said that it was probably robins, as he'd seen them in that corner of the garden, and that they laid their clutch over several days but didn't start incubating them until they'd finished laying, so that all would hatch at the same time.  I had no idea that eggs were able to survive in limbo, at room temperature, until the parent bird was ready to sit, but I don't know much about the domestic habits of robins.

I looked into the greenhouse this morning and a pair of anxious eyes looked back at me over the top of the nest, so they have started sitting.  I'll try not to disturb them, but I'm not prepared to vacate the greenhouse entirely and not water any of the plants until the robins have finished nesting.  I think the best thing to do will be to not ever look at them directly, and pretend I haven't noticed them.  They can't be afraid of me per se, because they follow me around the garden when I'm weeding.

Searching around the internet I gather that the female incubates the eggs, but that both parents help feed the young.  They can have 2-3 clutches in a season, and it sounds as though they build a fresh nest each time, which I suppose is more hygienic but extra work for them.  It will be interesting to see how they get on, and how we rub along together.  I've got a wooden frame with netting over it, previously used for keeping the birds off some strawberries.  Incubation apparently lasts 12-15 days, and once the eggs get close to hatching I'd better see about leaving the frame wedged across the greenhouse door, to deter the cats from going in if they hear the babies squeaking for food.  It's not as tall as the door, so there'd be a gap at the top for the adults to fly through, plus I'm sure they're bright enough to discover the roof vents.