The recovery of the Seychelles magpie robin population from a low of 12 in the 1960s has not always been a smooth one and problems and fluctuations are to be expected in a newly established population.
That is why we have been so excited by the excellent progress of the birds introduced to Denis. Of the initial 20 birds introduced only one was lost during the captive management stage following the very stressful process of the actual transfer, taking the island’s population to 19.
The birds rapid establishment of territories and subsequent pairing, however, gave the impression that breeding would very soon commence and see the population moving in the right direction.
This was indeed the case the first egg was found on August 4th and hatched on the 23rd of that month and developed well. At the same time 2 other territories established nests and commenced incubating their own eggs.
Sadly Catherina found the first chick dead on the ground below its nest in the first week of this month. It is not clear what happened:
- Perhaps the bird simply fell out of its nest as sometimes occurs but it seemed too young for that to yet be the case.
- More likely is that the bird was attacked and subsequently dropped by a Myna bird that was attempting to predate it. (see post of Monday 4th August for more information on the risk posed by Myna birds)
- However on close inspection of the chick two “prick” marks reminiscent of the bite of a centipede were found on the chick. Centipedes are abundant in the forest on Denis – what is not clear however is whether the bird was bitten in its nest hence causing it to fall out or was it bitten when already on the ground.
The bird has been sent for post mortem but it is more than likely that we will never know for sure what the cause was.
Anyway as you can see I have known about this for some time (and hinted about the bad news in my post of Monday 15th September); however I waited as, with the two other eggs having hatched, I wanted to give some good news with the bad.
The two other chicks developed well such that on the 14th of September they were both weighed, ringed and blood sampled in line with normal procedure for birds due to fledge. The chicks both appeared healthy and weighed 55 and 50 grams respectively.
I am therefore delighted to advise that one of our chicks fledged on Wednesday the 24th September and equally disappointed to have to tell you that sadly the second was lost. Catherina found the bird on the ground near its nest and whilst it could flap reasonably well it did not appear able to stand. This bird was not expected to have fledged for a few more days and so Catherina returned it to its nest thinking that it may have inadvertently fallen out whilst exercising its developing wings. Unfortunately the next morning the chick was again found on the ground in a much weakened state and still unable to stand - it died later that day. This body has also been sent for post mortem.
I must stress that in overall terms this is still good progress in terms of numbers so soon after the introduction as one can expect several mortalities post transfer and we suffered only one. It is nevertheless of considerable concern that we should lose 2 of the first three chicks. Mortality of chicks pre-independence can be quite high and it is for this reason that we typically don’t count a bird as part of the population until it reaches full adult independence. These losses, however, do raise concerns and we are already looking at means to reduce the Myna bird population earlier than we had previously planned.
In the meantime we have a further two territories showing signs of nesting so the work and hope continues. Check back regularly for updates on the status of our fledgling and the overall population.
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