Capturing the Diversity – How to monitor the bird nests

It took quite a while before we reached the first birds and they were situated on the first of a series of small stacks along the coast.  Again it was impossible to count every egg and chick, but they monitor using binoculars and count the adult birds.  But nearby, we started coming in to contact with the first birds who were nesting on the mainland.  The species here are black and brown noddies, some boobies and a few tropic birds.  Counting the noddy nests was a bit precarious as they do prefer cliffside perches, but the others tended to nest on the flatter ground.  To be accurate that the right nests are being properly monitored, numbered metal pegs were left at the nest site.  A database had been created by RSPB  that allowed the team to print out the records for the walk they were doing.  This would tell them where there were existing nests (with the numbers of the pegs they left there) that needed to be monitored again.  The job was to find these nests again; usually the team could remember roughly where they were but they also had the GPS coordinates in case they needed guidance.  The tags  meant that you could keep track of which nest you were looking at and work out the sequence.  Then they just had to update the sheet with the new status (number of eggs, chicks, fledglings or abandoned nests).  If the nest is empty the peg is removed, cleaned and used again somewhere else.  This did sometimes cause some problems for the database as peg numbers could get confused and give the wrong data on the printed out monitoring sheets.  One of my jobs was to clean up the mess in the database and help make the system more foolproof.  If a new nest was spotted on the walk then more details had to be captured; the location and the species of bird as well as the nesting status.  And the new peg number.

Tropic Bird chick on nest

The team recording the key data

Anselmo reports back from the edge

A glance up at the ghost colonies

The stacks – the safe place for the birds to nest

A typical nest being monitored

May look like a bathing pool but would be lethal

As easy to go forward as to go back

It was all rather complicated but did help to calculate the nesting success of different species.  It took some time for Edsel and myself to get our heads around how this could be used in GIS.  Yes, we could show the current status of nesting on the islands, but what was more important was that we needed to help them show where some species were getting more successes than failures, and any progression of nesting further and further on to the mainland or in new locations around the coast. Fortunately, the way the database was set up, you could slice and dice it whichever way you wanted, an Edsel had written a canny programme to automatically draw the results of these filters and label them uniquely.  In this way, monthly maps of nest status could be shown, different coloured dots for different species and the labels showing the status, and another map could show in a period how many nesting successes and failures there had been in each area.  Tara, when she did her studies quite successfully showed how the birds were gaining in their nesting confidence and moving further and further away from those refuge stacks they had once relied on to maintain the populations in the islands.