High density and successful breeding of Turtle doves Streptopelia turtur in Moroccan olive groves

Abstract

Background The turtle dove is a migratory species that has suffered a rapid decline principally across its Northern ranges, despite pronounced conservation measures. Consequently, it has been categorized as ‘Near Threatened’ in Europe. Degradation of breeding habitats and a decrease in food resources are listed as principal causes of this decline. Despite its importance, the productivity of the North African population is widely unknown. Here we present the first estimation of the density of the breeding population and the superior reproductively of Streptopelia turtur arenicola in Morocco and entire North Africa. Methods This study was carried out for two seasons 2018–2019 in the Saïss plain, central Morocco. Based on previous data, doves were monitored weekly, from early March to late August, in aquatic ecosystems (two dams and one river) and farmlands (cereals and orchards). The breeding population was censused using the “point-count” method, following a walked transect of 5 km in orchards, 7 km in cereal fields, and 3 km along the river. Equally, nests were searched in natural habitats counting riparian trees, forests, and ornamental trees, and in orchards based on the Common Birds Census (CBC) methodology, in which the singing doves, mating pairs, nesting, and/or feeding behavior were the most monitored signs to discover nests. In orchards, nests were searched line-by-line based on the rows of fruit trees. For each recorded nest, we note the breeding chronology, clutch size and incubation period, success and failure factors, dimensions, and vertical placement on trees. To evaluate the predictors of doves’ occurrence, we noted at each site the presence of cereals, water, human disturbance, presence of nesting trees, and predators. Results and Discussion In total, 3,580 turtle doves (22.37 birds/ha), including 240 breeding pairs, were documented. Nesting occurred mainly in olive groves, cereals were used for forage, and aquatic ecosystems for water sources. The nesting period lasted from late April to July (last fledglings). All nests were located on olive trees at a height of 225.30 ± 48.87 cm. The clutch size was 1.98 ± 0.13 (laid eggs/built nests), the incubation period lasted 14.16 ± 1.32 days, and the rearing period lasted 16.54 ± 1.76 days. The breeding success among the 240 monitored nests accounted for 73.84% during the nesting phase and 87.42% during the incubation phase; 71.5%% of nestlings have fledged, which is the highest success rate for turtle doves in Europe and Northwest Africa. Clutches were aborted mostly due to predation from snakes (7.5% of nests, 16.12% of eggs, and 5.63% of chicks), nest desertion (9.16% of nests and 5.37% of eggs), and marginally by the destruction of nests through farming activities. These findings are important for conservation plans, to restore turtle doves’ habitats in Europe, where the species is widely declining.

New data on the nesting sites selection and breeding success of three bird species in the riparian vegetation of Northwest African rivers

“…during the nesting, laying, and incubation of chicks. This approach was used by Mansouri et al (Mansouri et al 2021b) and Squalli et al (Squalli et al 2022d) to evaluate the breeding success and failure factors during each breeding phase, which is impossible with methods that use the number of fledglings for nests. In parallel, we documented human and natural factors suggested to influence the breeding success of the studied species.…”

“…have not yet been identified. Currently, cohabitation between avian species has received increasing attention, particularly in North African farmlands such as olive groves (Squalli et al 2022c;Squalli et al 2022d) and apple orchards (Mansouri et al 2022b). In our study, we demonstrated that the nests of cohabiting species were distributed differently among the monitored rivers.…”

“…They have been investigated in forests (Mounir et al 2022), wetlands (Cherkaoui et al 2018), farmlands (Hanane 2016), and urban ecosystems (Douini et al 2022). For example, Turtle doves have been studied in farmlands (Mansouri et al 2020;Mounir et al 2023), forests (Hanane 2018), and per-urban landscapes (Squalli et al 2022d). However, these studies focused on breeding biology, ecology, and geographical distribution, while nest-niche investigations are rare and limited.…”

“…Similarly, we compared breeding success and evaluated its predictors and influencing factors. We used Streptopelia turtur arenicola as a reference species because it is the most studied species in Morocco and North Africa concerning nesting strategies (Mansouri et al 2020;Squalli et al 2022d), nest niches (Squalli et al 2021;Squalli et al 2022c), and breeding success (Mansouri et al 2021b). Therefore, comparisons with this threatened species are suggested to clarify the nest niches of the other two passerines, which are considered less investigated.…”

Diversity and Abundance of Breeding Birds, Habitat, and Nesting Substrate Selection in Urban Areas: A Relevant Case from the Southern Slope of the Mediterranean

“…Before starting the statistical analysis, recorded species were grouped in orders and families as mentioned by [32,36,43]. Equally, the phenological status of breeding species (residents, breeders, migrants, and winterers) was noted based on the current phenology of Moroccan birds [45], while the conservation status of each breeding bird was cited following the latest IUCN Red list update [46]. Te number of breeding species and recorded nests were compared among nesting supports, including cavities and trees (exotic and natural plants) and urban breeding habitats via the one-way ANOVA test.…”