Temporal distribution of breeding in Bangalore’s birds

Here is a graph of the temporal distribution of breeding in Bangalore's birds. While compiling the Annotated Checklist of the Birds of Bangalore, had also put together the number of bird species breeding every month within a 40km radius from the GPO. Therefore thought that I would just put it together with Marshall's compilation of the number of species known to breed every month in India and see what emerges. This book is from 1877. So over this century, with all the climate change happening, has the breeding of birds in India shifted? Here is a small comparison between the present Bangalore and of the past India.

 

 

A difference of a month would mean that Marshall’s data was perhaps essentially from north India where the monsoon, and possibly the breeding, is delayed by a month compared to the south. The lowest in the breeding in the north is October and November, while at Bangalore it is December. This also parallels the withdrawal of the monsoons earlier from the north when compared to south India.

The wider seasons could also be influenced by the planned planting in Bangalore, of sequential flowering tree species, so that there are flowers right through the year: a horticultural concept introduced by GH Krumbiegel, after whom a road in Bangalore has been named. Creation of recreational gardens and parks is a part of urbanization, and in fact, the early drawings/paintings of Bangalore indicate a barren landscape. This shows that gardens and parks are a indeed a part of the urbanization of the Bangalore area.

The ‘concretisation’ of Bangalore is a different matter altogether, and recent data if compiled could perhaps show the impact of this too. One could expect a reduction in the number of species reported breeding here.  Lack of reporting could be one of the factors, but with digital photography becoming so pervasive, and social e-networking opportunities on the increase, it is unlikely.

The third graph below is how sample data from recent times would look. This is from the reports on BngBirds with alternate years considered, essentially over the past decade. The uni-modal distribution has become bi-modal with the original peak becoming a trough. This needs to be looked into more thoroughly.

 Graphed data extracted from: 
a collation of BngBirds email discussion group breeding reports, by Rashmi Sasidharan

 

 

 

 

 

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