A New Species of Sunbird?!?!?!?

Finding a new species of bird isn’t something most birders think of as a real possibility. Certainly not in this day and age. That being said, don’t tell Melissa. In the weeks and days prior to our trip to a remote section of the Rubeho mountains of Tanzania, Melissa would casually say, “you need to find a new species up there” which I’d always counter with, “there’s no way that’s going to happen” or “I’m just going to focus on our real targets.” Often I’d just ignore her comments altogether. After all, who actually finds a new species nowadays without extensive genetic or field work?

Our trip into the Rubeho Mountains was in search of some of Africa’s newest species. The Rubeho Partridge, discovered in 2000 and officially described in 2002, the Rubeho Akalat, discovered in 1989 and described in 2004, and the Rubeho Double-collared Sunbird, discovered in 2000 and described in 2016. Maybe Melissa was on to something after all. If there’s a place to find a few bird, this little-explored patch of forest , might be it.

The Mafwemiro forest, located southeast of Tanzania’s capital, Dodoma, stretches 11 km from north to south but is only 3.5 km wide at its widest point. This forest has rarely been visited by birders and in the last 20 years, only a handful have ventured into the forest. With extremely helpful logistics information from Louis Hansen (who had conducted research on the Rubeho Partridge here in 2018), Melissa and I made a trek into the forest in mid-April of this year (checkout @budgetbirders Instagram for a story on the trek). Being mid-April, we knew we’d probably have some issues with rain and we were right. Our hike in was dry, but the rest of our time in the forest involved rain, fog, or a combination of both.

After reaching the forest, we got to work looking for our targets. Our first encounter with Rubeho Partridge came quick and the Rubeho Akalat was easy, but follow-up efforts to find the partridge (we still didn’t have pictures or recordings) provided difficult. We also hadn’t found the Rubeho Double-collared Sunbird yet which prefers the edges of the forest. The next day it rained almost the whole day. We set out on the trails to look for the partridge and double-collared sunbird, but conditions were difficult and birding was tough. We returned to camp midday to try and seek some shelter and eat a quick lunch of rice and beans. Since the weather wasn’t improving, Melissa decided to stay back, but if you know me, you know I can’t sit still if there’s still a target to find. I wasn’t going to find a double-collared sunbird by sitting at camp, so back onto the trail I went.

I slogged up and down the muddy trail in the rain without much success. The rain kept coming. The camera was in a dry bag. The recording gear was in a dry bag. At around 4:30 in the afternoon the rain lightened up and some bird activity started to develop. I passed a small clearing in the forest and a Chapin’s Apalis dropped out of the canopy and landed about 2m away and started scolding me. I stood there contemplating whether it was worth getting my camera out of the dry bag or not. Then a second joined in and soon three Chapin’s Apalis were right in front of me, eye-level, causing a raucous. I thought, ok, this will be a decent photo; I’ll get the camera out.

As I was getting the camera out of the dry bag, a sunbird flew over my head and landed about 40m away. I didn’t see any yellow. Up until this point the only sunbirds I had seen in the forest had been Moreau’s Sunbirds, a species with very obvious yellow sides. Although I didn’t expect to find the Rubeho Double-collared Sunbird within the forest (it’s apparently an edge specialist), I still hadn’t seen an Eastern Double-collared Sunbird at this location so I found it intriguing enough to take a look. I raised my binoculars, but they were completely fogged so I grabbed the recently retrieved camera (obliviously the apalis had buggered off by the time I got it out of the bag) and snapped off two pics. I pulled it up on the screen and zoomed in to see what it was and honestly, was a bit confused. The bird had a tiny bill and a tiny red breast band. I thought, well, that’s not supposed to be here. I looked at the second pic, and sure enough, still a weird looking bird.

Luckily, the bird flew back over my head and landed nearby. I snapped off a few more pics and checked them. It still had a stout bill, still had a tiny red breast band, and what the heck, it also had a grey band and a yellow belly. What the heck is this thing? My first reaction: I need to take pics.

For the next fifteen minutes I watched the male sunbird and soon he was joined by a female. They flew around feeding on some small aerial insects that had started to swarm after the rain had subsided. At one point the male landed only a few feet above my head and started to call; Darn, the recording gear was still in the dry bag! I quickly got it out of the bag, but by that time the bird had stopped calling. Luckily it did do a series of calls later on that I was able to get a recording of (and a second recording the following day). The flock that the sunbirds were associating with moved on and I tried to follow, but soon lost them as they moved off trail. At that point, it was time to think through what I had just seen. Luckily I’m very familiar with almost all of Africa’s sunbirds after having been birding here for six months. I started thinking through what it could possibly be and nothing made sense. The bill was really stout, and what the heck was up with those red and grey bands? I kept trying not to jump to conclusions, but kept coming back to the idea that it might be a new species. At the very least, some new sub-species or hybrid.

I headed off down the trail to find Melissa who had started heading in my direction once the rain had subsided. We searched for the bird the rest of the afternoon, but couldn’t relocate it. The next day, using the recording I had made, we did have a single individual respond and briefly fly into view. Melissa got a quick look at it, but it didn’t stay for long and we didn’t get any more pictures.

Once we were back down the mountain, I sent the images off to a few friends to get some initial feedback and see if I was crazy. The three main options included a new subspecies, a weird hybrid, or a new species. I received a few responses, all of which were quite positive for it being a new species. It was exciting, but in typical nature, we were already in Kenya and in the midst of a whirlwind trip with new targets every day keeping me occupied. A friend, Stratton Hatfield, had been extremely helpful with providing me with up-to-date gen on my Kenyan targets so I sent the pictures to him to get his opinion as well. I think his jaw hit the floor and then he pretty quickly convinced me I needed to get the pictures sent out to a few more African ornithologists to get some more reactions/opinions. I sent out another round of emails and once again, there was a strong response that it most likely is a new species.

Although hybrids always need to be considered with wildly plumaged birds, the occurrence of a pair with the same structure and the very stout bill help to rule out this option. Potential hybrid combinations would be Collard or Banded (Green) Sunbird x Double-collared Sunbird type. In either of these options, the bill length would be expected to be in between these two parents, not shorter. Also, the calls of the bird were quite different than anything you’d expect from a Collared or Double-collared Sunbird.

Subspecies wise, the bird appears to clearly be an anthreptes sunbird. Therefore if it was a subspecies, it would most likely be a subspecies of Banded Sunbird. Based on the significant plumage characteristics, slight differences in calls, and pattern of distinctive “sister species” being found in these remote ranges, it is probably unlikely that it is just a subspecies.

Now that the discovery is over, I’m not entirely sure of what the next steps will be and when they will occur. Although it has been two months since I found the bird, I wanted to publically get the information out as more birders are starting to get interested in visiting this forest for the Rubeho Forest Partridge. It is my hope that now that others are aware of this bird, more people will have the chance to find and document it. Collection/research permits are a nightmare in Tanzania, so although I’ve started to figure some of that out, my initial goal of going back in July for a collection trip (which would have been starting this week) definitely isn’t happening. In the meantime, I’ve been enjoying sharing the news with other birders and hearing more thoughts on this pair of sunbirds. Of course, nothing is confirmed yet, and the general consensus on this bird might change, but for now, it’s been quite exciting. There’s a group of birders heading up to the area in just a few weeks so fingers crossed they can find this interesting bird again.

A few pictures of the male. Note the extremely short, stout bill, thin red breast band followed by a wider grey band and then an olive yellow belly/vent. The throat color tended to shin blue while the head/back changed from green or blue depending on light. The uppertail coverts and tail were green. The bird spent the majority of the time catching small flying ants around a small clearing in the middle of the forest. It stayed fairly low, mostly feeding 2-4 meters above the ground.

The female had a similar colored yellow/olive belly and vent that transitioned into a greyish upper breast and throat. The back often appeared green, while the head had a slight more olive tinge to it. Although I watched the female a few times, the majority of my time was spent observing the male. The female did not vocalize.

I’d like to thank all of the African birders who have offered their expert opinions, analysis, and thoughts on this bird, especially Neil Baker, Nik Borrow, James Bradley, Callan Cohen, Brian Finch, Louis Hansen, Stratton Hatfield, Adam Scott Kennedy, Rich Lindie, and Michael Mills. If you have any thoughts or opinions on the bird, feel free to reach out.