rubbish nest building

some birds are rubbish nest builders. This is a really shoddy example outside my work. From bitter experience woodpigeons are the worst. One built a nest in our front garden that was literally three twigs crossed over each other. The egg that it laid fell out, I carefully put it back in and then the cat down the road ate the wee bird when it hatched. I'm sure some sturdier nest construction might have saved it