Category Archives: Primate census

Dead Colobus Sightings

Whilst out in the field over the last 3 weeks GVI volunteers have come across three dead Angolan black and white colobus in the coastal forests surrounding Shimoni. This is a distressing and uncharacteristically high number to find in such a short period of time. Having spoken to the Colobus trust we discovered from their census data that there was a significant rise in the local Colobus population a few years ago.

Deceased Colobus found in Shimoni Forest

Deceased Colobus found in Shimoni Forest

Characteristically, following a rise in population there is inevitably increased pressure on resources such as food and water and as a result over the following years the population gradually returns to a sustainable number as the weaker and less successful Colobus are out competed. At present we believe that the abnormally high number of dead Colobus encountered can be partly explained by increased competition and pressure on resources following a population boom in the last few years.

Circumnavigating Shimoni Forest

About two weeks ago I wrote a few blogs about the colobus census we conducted in Shimoni east forest, for a masters dissertation.  Marta, who has been with us for almost 10 weeks, is doing a masters degree in environmental modeling, monitoring and reconstruction.  The aim of her dissertation is to assess the effects of forest fragmentation on the distribution of the rare subspecies of Angolan black and white colobus.


The main bulk of her practical work was the census, which we successfully conducted a few weeks ago.  To go hand in hand with that, and to provide the information she will need to utilise GIS mapping systems, we needed to get the GPS coordinates of the entire circumference of the forest.  It turned out to be a far more challenging task than we imagined…

Myself and Marta spent two days traversing the perimeter of the forest on foot, with out hand-held GPS recording coordinates every 10 seconds.  We started at the southern most point, and walked (vaguely) north-east, following the edge that borders Shimoni village, and ended at the very top of the forest, beyond the village of Anziwani.  It was enormously challenging!  The main reasons were because the edge of the forest is marked by very thick, very dense new growth, shrubs, thorns and thickets!  We were very glad to have a sharp panga (machete) with us.  The other main reason was because we are just coming out of the main rainy season, everything was green, thick and overgrown, and actually distinguishing between the technical forest edge, and the new growth and sporadic pockets of trees, was nearly impossible.


One of the easier sections… There was actually a path! 

It was an adventure though, and we both got back at the end of each day with scratches and bruises galore and very tired legs, but content in the knowledge that once her dissertation is complete, it will be an invaluable source and tool, in the fight to highlight the damage being done to this beautiful coastal forest, and home to these charismatic primates. 

Census – The Finale

Well hello again folks!

Apologies for not getting this blog up yesterday, we had issues with our elecricity…by which we mean we had none! But we’re back on line this morning so I can fill you all in.

So yesterday saw the conclusion to our colobus census in Shimoni forest! It has taken three days of long, hard transect traversing. We’ve tackled thorn bushes, impenetrable thickets and swarms of safari ants, but have come out at the end with some awesome data. Everyone is tired and covered in scratches, but we all had an absolute blast and got to see some fantastic sightings.


 A colobus on the move

It was quite sad for a portion of yesterday however, as the destruction that has happened and is still going on up on the northern edge of the forest is awful. There are huge sections that can hardly be called forest anymore. And both teams observed charcoal pits in various stages of completion. My team actually stumbled across two men that were in the process of digging one, but they bolted as soon as they heard us coming.

On a better note, both teams had great sightings of primates. Between us, we saw 5 colobus troops and 6 sykes troops, plus the usual collection of beautiful birds, sunis, eagles and the back end of a very large snake! So in total over the three days, we have seen 19 groups of colobus and 24 groups of sykes!


We have also come to the conclusion that we shouldn’t really be calling what we’e done a census. Because a census is when you do a total sweep of the area in one day, so the number of primates you see is, in theory, all the primates in the area. But because we’ve had to do it over three days (due to man power), we will still be using distance sampling techniques to get population density estimates.


Some of the victorious team members

Unfortunately due to the power situation, we have not had a chance to run the data through the distance sampling program so don’t have any results for you yet, but as soon as we do I shall let you all know!

Census Part II

Hello again,

Today was a continuation of the colobus survey we started yesterday in Shimoni forest. Yesterday we tackled transects 1, 2 and 3, plus two routes that fell between the main transects. Yesterday saw some tricky traveling, especially on the routes between the transects as they are not cut or marked. We were navigating through very dense bush and thicket using nothing but a compass (our GPS’s don’t work in the forest!), and keeping five groups at the same pace by literally counting paces. We worked out each one of the nominated pacers counted 21,000 of their paces!


 Having a quick rest…

So today we embarked on the top half of the forest; surveying transects 4 and 5, including the unmarked transects between 3, 4, 5 and 6. We thought we would be able to do transect 6 and one above it today as well, but unfortunately due to numbers we are going to have to finish it off tomorrow.


 Walking the transect (past an amazing tree!)

Today saw more sightings than yesterday, with nine groups of colobus! There were also nine groups of sykes recorded, unfortunately no baboons today though. The causal observations kept coming throughout the day, with a plethora of creatures great and small. There were multiple suni sightings (very small antelope), four zanj elephant shrews, red-capped robin chats, sunbirds and black kites. Having so many eyes in the forest at once is awesome!


 One of the many sykes monkeys

So I’m afraid you’re going to have to wait until tomorrow for any results, but as soon as we’ve processed the data we’ll get straight back to you.

Until tomorrow…

Colobus Census of Shimoni Forest

Today will be the first of a two part update on some exciting research going on in Shimoni Forest.  We are attempting to build on work previously done in 2001 by Julie Anderson and then in 2007 by GVI.  We are doing a colobus census of the whole forest!

Marta is a volunteer here with us for three months and is currently working towards her masters in environmental modeling, monitoring and reconstruction.  She contacted us asking if she could use her time here to do the field-work for her project in the forest, consisting mainly of a colobus census – we welcomed her with open arms!


 Preparing to synchronise watches

We timed the census for when we had the most number of people on the mainland, and managed to get a keen group of 15 people fired up and ready.  To do the census we require groups to conduct what is essentially a primate community survey along all of our regular transects, plus groups moving through the forest in between the transects following compass bearings, so a group every 100 metres.  Unfortunately our GPS’s do not work in the forest due to poor satellite coverage, so we had to devise a cunning system of counting paces and regular check points coordinated using mobile phones (on silent of course!), to ensure we were all moving through the forest at a similar pace. 


 The team heading in

In an ideal world, you would have enough people to do the entire forest in a single day, leaving you with a ‘snapshot’ population count.  We don’t have enough people so are having to do it over two days.  For those groups traveling between our regular marked and cut transects, it was pretty rough going – there was plenty of crawling through thickets and fighting through thorns.  However our sense of adventure and the belief in the value of the work prevailed, and lots of smiling faces headed back to base.


 Getting through one of the many thickets!

During the day five groups of colobus, ten groups of sykes and one group of yellow baboon were sighted.  Some of the other casual observations included a pair of zanj elephant shrews, hornbills, African fish eagles and lots of red bellied coastal squirrels!


One of the sighted colobus 

We’re all tired, but looking forward a second day out in the forest.  We really can’t wait to see the results and compare them with the previous years.  I’ll hopefully get a post out letting you all know how it went!