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Is there a link between Umzumbe and Chernobyl?

 The Umzumbe Roost on the KZN South Coast host’s between 1 and 1.5 million Barn Swallows every evening, the roost which is not accessible by vehicle and only accessible by crossing the Umzumbe River on foot. Unlike other large Swallow Roost’s is under no threat and hopefully will be utilized for many a year to come. My ringing site here is 900m from the roost (too great a distance to carry all the equipment to the reedbed, also security reasons for the vehicle) so has proved quite a difficult site to ring, but recent sessions since starting at the site has added another 589 captures in 6 weeks (2009 – 2010 season) to the data base all of this in the last month of the 2009 to 2010 season. The birds captured here have thrown up some very interesting questions. 2 of the swallows had only one leg each, a most unusual find in these birds, according to Anders Pape Moller (University Pierre & Marie Curie, Paris, France) he has only recorded this in 2 birds of the tens of thousands of birds he has ringed. After studying a paper that was written by Anders along with T.A.Mousseau (Department of Biological Studies, University of South Carolina, U.S.A), F. de Lope (Universidad de Extremadura, Avda, Spain) and N. Saino (Universita degli Studi di Milano, Italy), of a study done after the Chernobyl disaster of 1986, the study started in 1991 and finished in 2006. Here it was noted that the Barn Swallows odds of disabilities and defects rose dramatically. Among the problems were missing legs, deformed beaks, bent and uneven tail streamers and partial albinism or leucistic feathers. The number of swallows with one or two white feathers mixed amongst their blue and red feathers is about 2%, at Chernobyl this rose upwards of 15% of the birds during the study period, another site or control site was used in the Ukraine approximately 220km’s away. It was also noted that a large number of birds developed a reddish colour on the belly, more common in the Ukraine than elsewhere, this however cannot be solely attributable to the Chernobyl Disaster as an interbreed between different sub species of swallow can occur, about 5% of the Ukraine’s population shows this trait, whereas in western Europe the number is down to 1%. The study showed that the swallows had a higher birth defect rate than any other part of Europe.


The Umzumbe roost has now started to ask questions as to where a lot of these birds breed in Europe, due to the high number of birds with the odd white feather where it should not be, the 2 birds with only one leg, a large number of swallows with inconsistent tail streamers along with the reddish underparts could lead us to suspect that these swallows are from the Ukraine and in particular from the Chernobyl area. In total 12% of the birds ringed at Umzumbe have shown variations in leucistic feathers, tail streamer problems and the 2 one-legged birds. In addition to this the colour variation on the belly ranging from pale reddish to reddish occurred in 27% of the birds ringed. We do know that birds from the Ukraine have been recaptured in Johannesburg, Pretoria, Lake Kariba, Gabarone, Harare and Durban, unfortunately ringing is not as common in the Ukraine as it once was but we can only wait and see if the current data can be proven.


Considering the distance between the Umzumbe and Mt. Moreland Roost’s is 120km a variation in colour between the birds at each site could be used as a study roost (Umzumbe) and a control roost (Mt. Moreland). All birds were handled, ringed and colour graded by myself to get a consistent colour coding. The birds were sorted into 4 different categories of colour on the belly, the first was what we expect on the birds and that is white, the second I called buffy where the feathers were almost a dirty white, the third I called Pale Reddish and these feathers had a definite reddish colour to them but not a deep red colour, the fourth variation was classified as dark reddish and these birds had a more even reddish colour on the belly and just a little lighter shade to the red on the throat.




                    Umzumbe Roost          Mt. Moreland Roost


               White Belly                      52.40%                71.70%

               Buffy Belly                       20.60%                20.75%

               Pale Reddish Belly            21.60%                  5.66%

               Dark Reddish Belly               5.4%                  1.89%

Table showing the % of birds ringed at the 2 locations and the colour variations on the belly


Over the years I have realized that the Barn Swallow can be used to indicate impending changes in the weather. How they can sense this only they will know but two instances are worth noting. The first being 8 years ago when during February the swallows near Port Shepstone were behaving as if it was time to migrate (at least 4 to 6 weeks early) they were sitting on telephone lines and having a feeding frenzy over the sugar cane, the next day they had all disappeared. At the time you think that is strange, however that evening a storm hit the South Coast uprooting trees and lifting roofs off houses, somehow the birds sensed the change in the pressure and moved north early to avoid the storm. The second instance was in November 2009 at Mt. Moreland, we ringed on the Friday and Saturday evenings where good numbers of birds were caught, but on going through the data it could be seen that most birds had not started their primary feather moult, normally by this stage they should be onto the third or fourth feather (as seen from previous seasons). On the Sunday evening very few birds came into roost, then on the Monday even less arrived, then on the Tuesday very wet and cold weather arrived and lasted for 5 days. Once the weather had warmed up and the food supply was again present the swallows arrived back in their usual numbers and in December we noted that they had started to moult their primary feathers. In both cases this begs the question as to how they could sense the change in the weather, and does this influence their migration.