Rapid increase in numbers and change of land-use in two expanding Columbidae species (Columba palumbus and Streptopelia decaocto) in Algeria

Bendjoudi, D., Voisin, J.-F., Doumandji, S., Merabet, A., Benyounes, N. & Chenchouni, H. (2015). Rapid increase in numbers and change of land-use in two expanding Columbidae species (Columba palumbus and Streptopelia decaocto) in Algeria. Avian Research 6(1): 18.
doi: 10.1186/s40657-015-0027-9 (Open Access)

Background:

Investigating population ecology of urban bird species, particularly the invasive and expending species, is the key for the success of urban management and planning strategies.

Methods:

Populations of two Columbidae species, the Woodpigeon (Columba palumbus) and the Eurasian Collared Dove (Streptopelia decaocto), were monitored from 1992 to 2010 in the Algiers Sahel, the Mitidja Plain and surrounding areas (Northern Algeria). Monitoring of species densities was performed by the mapping-plot method. The foraging flight routes of Woodpigeon and the distribution of Eurasian Collared Dove were assessed by systematic observations.

Results:

The number of counted birds was statistically constant at first years of the survey, and then increased significantly, beginning from low numbers, their densities accelerated sharply between 2001 and 2006, then reached to an equilibrium state. The significant increase in Woodpigeon’s population could be explained by the reduced hunting pressure and by species adaptation to new food resources provided by nearby agriculture. Indeed, monitoring of flight directions of the species revealed the use of agricultural landscapes and habitats, which is a good indicator explaining adaptation and trophic niche of the species. The occurrence of the Eurasian Collared Dove in Algiers began in 2000. Its density experienced a rapid increase with similar trend pattern as that of Woodpigeon. Its distributional range is confined mainly in suburban environments of the Mitidja Plain.

Conclusion:

The modifications of habitats, urbanization increase and the lessening of hunting in the Mitidja Plain facilitated the rapid expansion of the Eurasian Collared Dove and Woodpigeon as well contributed to the increase in their numbers over time.

Eurasian Collared Dove (Streptopelia decaocto), Bouira, Algeria

Eurasian Collared Dove (Streptopelia decaocto), Lakhdaria, Bouira, Algeria (Abdelaziz Mazouz, flickr)

Dynamics of invasive and expanding species in the Mitidja Plain, Northern Algeria

Bendjoudi, D., Chenchouni, H., Doumandji, S., & Voisin, J.-F. 2013. Bird Species Diversity of the Mitidja Plain (Northern Algeria) with Emphasis on the Dynamics of Invasive and Expanding Species. Acrocephalus 34: 13–26.
doi: 10.2478/acro-2013-0002

Abstract & full text (Open Access):

This treatise investigates the poorly studied bird fauna of Mitidja Plain (Northern Algeria), with particular notes on the occurrence and expansion of new and alien species. Direct observations, supported by ornithological surveys carried out by Progressive Frequential Sampling (PFS), a version of a point count method, have allowed us to identify 125 bird species. These represent 31% of all species known from Algeria. The species recorded belong to 14 orders, 39 families and 37 genera. According to their biogeographic origins, 36 are Mediterranean, 32 Palearctic, 24 Holarctic, 17 European and 16 of European-Turkestani origin. The Mitidja Plain holds 60 resident-breeder species (48% of all registered species) and is a transit zone for many migratory species (summer and winter migrants constituting 20% and 14% of the total, respectively) and occasional visitors (RA = 12%). Among recently expanding species (introduced or local), the Collared Dove Streptopelia decaocto and Wood Pigeon Columba palumbus, sampled by the spot-mapping method, experienced a very rapid population growth. The first observations of the former were made in 1996 in Algiers. Its numbers experienced a steep increase after 2002, starting from 5.75 pairs/10 ha to reach up to 31.5 pairs/10 ha in 2006. The same applies for the Rose-ringed Parakeet Psittacula krameri, surveyed by direct-count at roosting sites. This species has been able to increase and reproduce since its first introduction into the wild in 1996. The increase in study species populations, especially the Rose-ringed Parakeet, may derive from good weather conditions that favoured the species through providing better feeding conditions, thus high reproduction outcomes.

Rose-ringed Parakeet - Perruche à collier (Psittacula krameri), northern Algeria

Rose-ringed Parakeet – Perruche à collier (Psittacula krameri), northern Algeria (Mohamed Missoum‎)

Population growth of Rose-ringed Parakeet (Psittacula krameri) in Mitidja Plain and surrounding areas of Algiers, based on the counts of individuals on roost-sites

Population growth of Rose-ringed Parakeet (Psittacula krameri) in Mitidja Plain and surrounding areas of Algiers, based on the counts of individuals on roost-sites (Bendjoudi et al.)