A Home For The Lesser Kestrel
Project location: ITALY
Project start date: September 2006 - Project end date: September 2007
Project number: 2006-24
- Please click here to dowload the final report for this project (pdf 4MB)
- Please click here to open a 2010 project results update (pdf 1MB)
The project "A home for the Lesser Kestrel - practical steps to protect the Lesser Kestrel Falco naumanni in Apulia and Basilicata" is the most important conservation project of the last 10 years targeting the Lesser Kestrel in the Murge region between Apulia and Basilicata.
This vast, karstic plateau hosts Italy's most important population of Lesser Kestrel. Most peculiarly, this population almost completely depends on man for its survival. Indeed, the entire population breeds in the historic centres of the towns of the Murge, while it feeds in the vast prairies that ring these towns and make up the so-called pseudo-Mediterranean steppe.
The co-existence between man and the Lesser Kestrel is currently threatened by transformation in both the agricultural and livestock industries, and by changes in building and renovation techniques. In particular, the renovation of historical buildings has had a strong impact on Lesser Kestrel colonies, frequently leading to the loss of entire clutches due to renovation work being undertaken during the breeding season. Furthermore, in order to keep out nuisance species such as Feral Pigeons, the architectural criteria currently being used eliminate any cavities that could be used as nesting sites by Lesser Kestrels.
The use of nest boxes has, from the very start, seemed like an important conservation tool, since they are easy to install (even for non-biologists, such as construction workers) and inexpensive.
The current project studies for the first time the large-scale use of wooden nest boxes on the part of Lesser Kestrels, and evaluates their efficacy during the first year of the effort.
The nest boxes were built thanks to the experience gained over the last several years by Dr. Pino Giglio, who in the late 1990's had started a nest box project on a local scale, using different materials for, among other things, the roofs of the nest boxes.
The unpolished wood to be used to build the nest boxes was delivered to LIPU offices in Gravina, and the roofs of the nest boxes were covered with a waterproof sheath (previously, pantiles were used, which made the boxes better protected and more durable).
Nest box model
Furthermore, four small disks were placed at the foot of the nest boxes in order to prevent it from touching the ground, and keep excessive humidity at bay.
The width of the entrance hole - 6 cm - makes it accessible to Lesser Kestrels only, and keeps out unwanted species such as Feral Pigeons Columba livia var. domestica, which share the Lesser Kestrel's urban habitat. A lateral window, 10 cm in diameter,, and which can slide open, is placed on one of the sides of the nest boxes, making it possible to better inspect its contents, clean it, and ring any chicks that might be present. Each nest box has been numbered, so that they can be easily monitored during the nesting season.
As early as October 2006, LIPU contacted the necessary people to have access to places in which the nesting boxes can be located. In the case of public buildings (schools, town halls, offices of the Alta Murgia National Park), LIPU had to make formal written requests, which at times slowed down the installation process due to delays in obtaining the needed authorisations.
The installation phase began on February 22, 2007, and continued through the entire month of March, while in April LIPU installed the nest boxes for which the sites it had originally chosen were no longer available. At the last moment, in February-March 2007, several of these sites suddenly became unavailable due to repair work on the buildings on which they were located, so that about 65 nest boxes (32.5% of the total) had to be installed later than planned, and in some cases in less than optimal sites. This delay probably had an impact on the occupation rate, although in two cases - one in Altamura and one in Acquaviva - nest boxes installed respectively on April 13 and April 14, 2007 were occupied.
LIPU installed 200 nest boxes in the towns of Gravina in Puglia (n=102, 51% of the total), Altamura (n = 50, 25% of the total), Acquaviva (n = 22, 11% of the total), Cassano (n =12, 6% of the total), Laterza (n = 14, 7% of the total).
LIPU gathered basic data on breeding, including clutch size, date of egg laying, hatching success, breeding success (number of fledged juveniles/number of pairs that laid eggs). A nest box was considered occupied only if at least one egg was laid in it.
For the town of Gravina in Puglia, where the majority of nest boxes were placed, LIPU plotted the distribution of nest boxes in the urban.
All 200 nest boxes installed during the project were checked at least twice between 15 May and 20 June. This is the peak period for egg laying (between 15 and 20 May) and for the first phases of chick rearing. If no egg laying occurred during this period, the nest box was no longer checked.
Additionally, the same data was gathered for 37 ‘natural' nests in the colonies at Gravina in Puglia and Altamura, and for 10 nest boxes installed in 2004.
Each occupied nesting site was classified as belonging to one of the following four categories : a) attic, b) ledge, c) cavity, d) artificial nest.
A total of 16 nest boxes were occupied by Lesser Kestrels (8% of the total), while 39 were visited by them. 11 nest boxes were occupied in Gravina in Puglia (10,8% of the total), 2 in Altamura (4% of the total), 3 in Acquaviva delle Fonti (13,6% of the total), while none were occupied in Cassano delle Murge and in Laterza.
A total of 53 eggs were laid, 18 chicks hatched, and 11 juveniles fledged. LIPU found pellets, feathers, or food remains in visited nest boxes.
The occupation rate of 10 nest boxes that have been in place for three years or more is 60%, which shows the importance that they assume over time, and proves that they are used to a much greater extents after they have been in place a few years.
The percentage of visited nest boxes was 19.5 % (39 nests). If we exclude the 65 nest boxes that were installed late, and thus take into consideration only the 135 that were installed on time, the occupation rate increases to 11.9%. If we look at the 41 buildings on which nest boxes were installed 41, the occupancy rate of buildings is 24.4 % (10 buildings).
Of the 16 occupied nest boxes, 4 were subject to a certain degree of disturbance due to maintenance work on the buildings on which they were placed. This probably led to the abandonment of the nest (reproductive success was thus nil), and prevented other nest boxes located on the same buildings from being occupied.
Our data and results lead us to suggest certain steps that could be taken in order to improve the occupancy rate of nest boxes. They are detailed below:
1- The buildings on which nest boxes will be placed should be within 100-200 meters of another building that already hosts several breeding pairs of Lesser Kestrels;
2- One should make sure that no renovation or maintenance work is scheduled to take place on the chosen building during the nesting case; should such work be scheduled, nest boxes should not be placed on the building, or at the very least they should be located in a part of the building that will not be affected by this work;
3- Nest boxes should preferably be placed in partially shaded areas, in order to avoid excessive exposure to sun, and to keep temperatures inside the nest box low enough to prevent damage to chicks;
4- Nest boxes should be in place by February-March, and preferably by January, since nest boxes installed in April have very low occupancy rates.
In light of the experience acquired during the 2007 breeding season, LIPU suggest that nest boxes that are unlikely to be occupied due to their location be installed elsewhere. In some cases, nest boxes that were most exposed to poor weather might benefit from maintenance work.
The occupancy rate of the nest boxes installed for the project was not particularly high. Eggs were laid in only 16 nest boxes, while at least 23 other nest boxes that were visited by Lesser Kestrels were abandoned early in the breeding cycle.
As shown by numerous studies on the use of nest boxes by passerines (Lack 1955, 1958, Perrins 1979, Ulfstrand et al. 1981), occupancy rates during the first year is never particularly high, and it is often necessary to wait 1 or 2 additional years for nest boxes to be fully accepted by birds. The Lesser Kestrel is no exception. Indeed, of the 10 nest boxes that had been in place for at least 3 years, 6 were occupied (60%). Additionally, studies on the breeding biology of the Santeramo in Colle colony between 2003 and 2005 showed that nest boxes had an occupancy rate of 12% in the first year, 38% in the second year, and 58% in the third (Bux et al., 2005).
Furthermore, studies conducted so far show that the tendency to occupy new nesting sites (such as nest boxes) is highly dependent on the degree of success of the breeding season: years with a low hatching rate and breeding success - due to unstable weather or lack of food - are also the years in which nest box occupancy rates are lowest (Bux in prep.).
Comparing the breeding parameters recorded for each type of nesting site seems to confirm this hypothesis: although the breeding success recorded for next boxes is never higher than for other types of nesting sites, it does not vary significantly for the breeding success recorded for natural sites such as cavities and attics, particularly with regards to the latter.
In summary, we have found that wooden nest boxes are a useful conservation tool, since they help limit the disappearance of nesting sites for Lesser Kestrels, and they can be used successfully in those cases in which rapid intervention is critical, such as for buildings under renovation. It is thus necessary to continue monitoring the nest boxes in order to evaluate their ultimate acceptance rates, and to continue to improve on their design and placement.
Distribution of nest boxes in Gravina in Puglia. Red dot: unoccupied nest box; Green dot: nest boxes that have been occupied or visited by Lesser Kestrels; Blue dot: nest boxes installed prior to 2006 (outside the scope of this project). The width of the circle indicates the number of nests per site: small circle: 1-2 nests; medium circle 3-6 nests; large circle 7-10 nests.
The inside of an artificial nest box with an adult female and four chicks (approximately 10 days old)
LIPU contacted a total of 43 schools, including 9 in Acquaviva delle Fonti, 10 in Altamura, 5 in Cassano delle Murge, 8 in Gravina in Puglia, 4 in Laterza, and 7 in Santeramo.
LIPU sent a fax to the principal of each school contacted in November 2006.
21 classes belonging to 7 different schools (4 in Gravina in Puglia, 1 in Cassano delle Murge, 1 in Acquaviva delle Fonti, and 1 in Altamura) agreed to participate in the project. Of the 21 classes that participated, 11 were middle schools (4 sixth grade, 2 seventh grade, 5 eight grade), and 10 were elementary schools (6 third grade, 1 fourth grade, 5 fifth grade).
The lectures in which the project and contest were presented all took place in March, except for one, which was delayed numerous times by the teachers and took place on May 4.
Upon request from the principal, on May 8 we gave a lecture - outside the scope of the project and the contest - to 6 classes of the "Federico II di Svevia" high school in Altamura.
During the month of May, six classes from Gravina di Puglia and two from Cassano delle Murge made field trips to see Lesser Kestrel in the Murgia region of Bari province.
Lectures presenting the project were followed with great interest and enthusiasm by all the students, although in spite of their commitment, there was very little participation in terms of submitting entries for the contest.
Only one school kept its commitment, and submitted numerous entries by fax.
Class meetings included a 20-slide power point presentation, with the logos of LIPU and the project's financing institution - Fondazione Petretti - displayed on each slide. LIPU explained the goals of the project, as well as the Lesser Kestrel's breeding biology, its global importance in terms of conservation, its phenology, and the operational modalities of the "A home for the Lesser Kestrel" project. In some cases, class presentation were followed by field trips to areas of the Murge region where Lesser Kestrels can be observed in their natural habitats, in order to familiarise the students with the birds' natural history.
During the class presentations, LIPU handed out a fact sheet with information on the "A home for the Lesser Kestrel" project, describing the project itself as well as the Lesser Kestrel, its distribution, identification, migration, breeding biology, and food.