Lappet-faced vulture nestling found dead on the nest.

Lappet-faced vulture nestling before (note the shiny, open eye) and after (desiccated eye and dried body parts) its death from an unknown cause. ©ESO, IAR.

As mentioned in a previous blog (here), one of the nestling Lappet-faced vultures we fitted with a tracking device died on the nest.  

The way that transpired was: we (Environment Society of Oman vulture study workers and Environment Authority staff) visited the nest, and fitted the chick with a tracking device on 11 May.  All was fine.  We set up a trail camera to monitor the nest. The tracking device provides not only location data, but also information on acceleration in three dimensions, so by monitoring that we can determine when the device is no longer moving.  Of course, a non-moving device suggests that the bird might no longer be alive or the tag has fallen off.  

Twenty-three days after fitting the transmitter, the tracking data suggested that there might be something wrong, a team when out to the nest and found the chick dead.  The team collected the chick and took it to a vet for a necropsy.  Unfortunately, the extreme heat had caused the carcass to deteriorate, and the results of the necropsy were inconclusive.   We had also set up a trail camera at the nest, but it showed the adults (or at least one of them… we couldn’t tell because birds can’t be recognized as individuals… at least, not by us) visiting the nest regularly.  However, the camera memory filled and we had no images from the likely time of the death of the bird.

We really don’t know the cause of this bird’s death.  It could have been a natural event, but when we fitted the device, the bird seemed in good health (photo above).  It could have been that the parents brought in some food that was somehow contaminated, and that poisoned the nestling.  Although bird parents can abandon their chicks if disturbance is too great that does not seem to be the case here because the adults were photographed arriving at the nest after we fitted the tracking device.  It is also possible that one or both of the parents died for some reason (we know of Lappet-faced vultures being electrocuted nearby), and there was not sufficient food for the chick.  Like I said, we simply don’t know.  

Last year a similar mysterious death of a seemingly healthy Lappet-faced vulture nestling occurred in Dhofar.  Because that bird was not fitted with a tracking device, we only learned of its death after some weeks, and by then had no chance of guessing at the cause.  At least one goal of our work is to better understand what threats (e.g. disturbance, poisoning, and persecution) face Lappet-faced vultures in Oman, and work to lessen those threats.