Our Welcome swallows have advanced young - second breeding in Spring 2015

Welcome swallow on nest with food, 7th November 2015

I was on my way to do some shopping this morning and smiled as one of our Welcome swallows zipped off it's nest.  But I thought I saw movement on the edge of the nest a few moments after the adult bird left.  I stopped to watch for a few seconds.  A slight movement gave it away - there are now young in the nest again ! 

I quickly grabbed my camera and watched the nest for movement through the viewfinder.  Without warning, one of the adults zipped back to the nest, returning with food.  

Adult Welcome swallow feeding young, 7th November 2015 

 At least three bright yellow mouths appeared waving over the edge of the nest, and the adult promptly fed the closest mouth.  It paused for a few moments to look at me before zooming off again.  

This observation confirms second clutching in Welcome swallows nesting in Lake Macquarie, NSW in 2015.  It's nothing out of the ordinary or worth writing up; it's simply an interesting anecdote concerning this species.  They nested for the first time here last year.  They built their nest and successfully raised a single clutch of young.  The adults and (I suspect) the first years young, have roosted in the immediate vicinity most nights ever since.  They over-wintered here, using the nest as a refuge during the coldest nights of the year.  I am unable to identify the individual birds confidently.  However I could pick the original parents from the first year's offspring. 

The most interesting observation was the first year when the nest was built, they only had a single clutch of young.  By using the nest again, they have successfully raised one clutch and are well on the way to rearing a second clutch of young.  It will be interesting to see if they can successfully rear the second clutch, and maybe even start a third?  

This raises a few interesting points in my mind;

1.  Is the energy expended by building a nest equivalent to raising a clutch of young?

2.  How important is a nest to the long term survival of Welcome swallows in the Lake Macquarie area?  As mentioned above, we had Welcome swallows roost in the immediate vicinity of the nest most of the winter.  On the coldest nights they actually slept inside the "abandoned" nest.  Would they had fared less well over the winter if they didn't have a nest to retreat from the coldest nights?  Would they have survived the winter at all?  Would the metabolic energy saved by using the nest to keep warm on the coldest nights mean the difference between being able to raise a single clutch of young or multiple clutches in the coming breeding season?  Was the roosting behaviour merely territorial behaviour intended to ensure the adults would maintain their territory?     

3.  There are many confounding factors; the most obvious one that I cannot uniquely identify each individual.  Their plumage is not uniquely marked between individuals and they are not leg-banded.  This means that nothing I note about them can be considered scientifically valid.  For example, I do not know if these are even the same birds that built the nest!  For all I know they could be another pair of adult birds, or even the young from last year.  

4.  I don't know how old the birds were that originally built the nest.  Were they young birds and this was their first attempt at nesting?  Were they older birds, that built their nest here because their last nest was destroyed elsewhere? 

5.  There are many other points to consider such as rainfall and insect abundance.

It's a fascinating thing to watch the seasons pass and the local wildlife as they share our homes and lives, so often unseen.