Barn Swallow; Golondrina Común

When the Swallows arrived this may a pair started to construct a nest on our balcony. It eventually reached about the 50% mark before being abandoned. We thought they had moved back into the original nest where 4 young were later produced but after fledging we had maybe a dozen youngsters on our covered washing line every night so presumably they had nesting sites nearby but we had the favoured overnight roosting location. This pic was taken when they first started building.