It is always a treat to find a rare bird. When I was in Tanzania nearly every bird species I observed was a rare (in most cases brand new) species for me. It appears that one species I observed is also a rather rare species for Tanzania.
On September 25, 2010 I traveled from where I was working (I will talk more about that later) to visit my friend Steve Windels who was working at a Wildlife Management Area near Lake Manyara in north central Tanzania. That afternoon we went for a walk to look for birds along the lake shore. As we were walking we talked about the birds that Steve had observed at the lake. He mentioned that he had observed Slender-billed Gulls, but added that according to the range map in the bird book, Birds of East Africa, they shouldn't be here. I passed it off as a situation where the distribution of this species was poorly known and it probably had been recorded at the lake before but the maps in the field guide were out of date. Shortly after our conversation a pair of gulls flew by that appeared to be Slender-billed Gulls. I snapped off a few photos as they flew by.
Upon returning home, I figured I would do some research to find out about the current status of the Slender-billed Gull in Tanzania. I checked the Tanzania Bird Atlas Project website and blog and found out that the first recorded observation of a Slender-billed Gull had occurred in March of 2006 at Lake Victoria. There has apparently been only one observation of this species since then so our observation would represent the apparent third record for Tanzania.
The Black-headed Gull, which is more common here, would not have such an elongated face and long bill, there is usually a black earspot on Black-headed Gulls in winter plumage (breeding birds would have a black head), and would have a dark eye (although faint, it appears that these birds do have light colored eyes).
I wish I had been more cognizant of the status of this species in Tanzania before we saw the birds. I was overwhelmed at that point with the number of birds we were seeing that afternoon and I have no notes about this observation. I know there were at least two individuals from the photos I took, but there may have been at least one more individual that flew by.
This was certainly not an species I would have considered the most exciting of the birds I found during my stay in Tanzania, but now, after having found out how rare it is to see there, it is a rather exciting observation indeed.