Project Report "Monitoring of Aquatic Warbler Breeding Groups in Ukraine in 2017” Report prepared by Dr. Poluda Anatolii Participants of survey: Poluda Anatolii Khymyn Mykhailo Iliukha Oleksandr Korkh Yurii Leheida Ivan Frankov Serhii Ukrainian Society for the Protection of Birds KYIV, 2017 2 Summary In 2017 the most important breeding areas of both population groups of Aquatic Warbler in Ukraine were surveyed. In particular, eight breeding areas th th of the Desna-Dnipro population were visited from 1 till 8 June (7 days evening censuses). Four persons participated in the survey. Monitoring of the th th Prypiat population groups was performed from 23 June till 2 July, and nine evening censuses were carried out. Also four persons participated in the survey. The censuses covered 865 ha out of 1,180-1,280 ha of suitable habitat in the breeding sites of Desna-Dnipro population (66-68%). 102 males were recorded there. In the breeding sites of Prypiat population 542 males were recorded on 966 hectares. This is about 14-15% of the total area of suitable habitats of the Prypiat population (6,615-6,715 ha). During the survey of the breeding sites of the Desna-Dnipro population hydrological conditions were not optimal for most parts of the surveyed area. Due to artificial structures (sluice, dam), optimal conditions were only found in the breeding sites UA-05. Udai valley “Dorohinka-Monastyryshche”, UA-08 “Horodok” and UA-06. Halka valley “Halka”. However, in the last site no AW have been registered. Three breeding sites were completely dry – in the key territory UA-01. Supii valley “Vilne-Berezanka” only 2 males were counted, in UA-07. Perevid valley “Paskivshchyna” – only 1 male, in UA-04. Supii valley “Voronky” – 0. In 2017 in two out of eight breeding sites no AW have been recorded (UA- 04. Supii valley “Voronky” and UA-06. Halka valley “Halka”). In the latter case, the reasons for this are not clear, since the conditions for nesting were optimal. The number of birds declined catastrophically in five breeding sites – Supii valley: UA-01 “Vilne-Berezanka”, UA-02 “Bykiv” and UA-03 “Bilotserkivtsi”, UA-07. Perevid valley “Paskivshchyna”, UA-08 “Horodok”. Only in one territory (UA-05. Udai valley “Dorohinka-Monastyryshche”) the situation was better than in the previous two years. The total AW number of all the eight surveyed breeding sites of the Desna-Dnipro population was estimated at 217-275 males only . For comparison, in 2016 the AW number was estimated at 153-220 males, in 2015 – 300-375, in 2014 – 450-500. In 2017 the survey of AW breeding territories of the Prypiat population were carried out at 15 breeding sites, but two of them were only visited during daytime (UA-11. Upper Prypiat, area to the east from Turiia mouth and UA-29. Stokhid valley, area near St.Chervyshcha). During the breeding season, the situation with the water level in the AW sites of the Prypiat population was similar to that in the breeding territories of the Desna-Dnipro population. For the fourth consecutive year, no spring floods occurred in the Prypiat river basin. This often leads to burnout of the AW habitats. 3 During our surveys, optimal water conditions occurred only in two AW sites (UA-24 lakes Bile and Pisochne and UA-25 Chornohuzka valley “Tseperiv-Baiv” and on a small part (not more than 10%) of UA-14 “Vetly- Birky”). At the other breeding sites the water level was below the ground. In 2017, the AW number has increased in almost all the breeding sites compared to the last year's season. Only in UA-09 “Richytsia-Pidhiria“ the number has not changed, and UA-24 lakes Bile and Pisochne and UA-25 Chornohuzka valley “Tseperiv-Baiv” numbers have slightly decreased. The total AW number of the Prypiat population was estimated at 2,850-3,280 males (Annex 2, Table). The total AW number in Ukraine in 2017 is estimated at 3067-3555 males. We are very grateful to our German colleagues and Ukrainian Society for the Protection of Birds for the financial support of this survey. 4 Introduction There are two population groups of breeding Aquatic Warblers in Ukraine – the Desna-Dnipro and the Prypiat population. In recent years, when surveys of the two groups were performed, the size of the Ukrainian population was estimated as follows: 3,800-4,365 males - in 2008, 4,000-4,750 in 2009, 4,200- 4,900 – in 2010, 3,450-4,050 – in 2012, 3,400-3,780 – in 2014, 3,050-3,375 – in 2015, 2,010-2,315 – in 2016 (the actual number this year, most likely, was 200-300 males higher). Terms and Method of Research In 2017 the most important breeding areas of both population groups of Aquatic Warbler in Ukraine were surveyed. In particular, all eight breeding th th areas of the Desna-Dnipro population were visited from 1 till 8 June (7 days with evening censuses). O. Iliukha, S. Frankov, M. Khymyn and A. Poluda participated in the survey. Monitoring of the Prypiat population group was th th performed from 23 June till 2 July (9 days with evening censuses). M. Khymyn, Y. Korkh, I. Leheida and A. Poluda participated in the survey. AW censuses are conducted with the method developed by the International Working Group on the Aquatic Warbler (Aquatic Warbler Conservation Team, 1999). In the Aquatic Warbler habitats 200 m wide and 1- 1.5 km long transects were surveyed. These surveys began 30-40 minutes before sunset. The number of males at a site was calculated by extrapolating the results of transect counts to the entire area of suitable AW habitat at the site. Besides assessing the number of birds in a definite grouping, the state of plant associations and the hydrological conditions of the habitat were determined (pits were dug on the most nesting areas to control the water level). Results and Discussion Desna-Dnipro Population During the survey of the AW breeding areas (01.06.-08.06.2017) hydrological conditions were not optimal in most parts of the sites. Since four years (2014-2017) there have been no spring floods in this region. In spring of 2017 the water level in the valleys of small rivers was significantly lower than 5 before the period 2014-2017(Annex 2, Fig. 1). Due to that situation some breeding territories were completely burned. An illustration of the unfavourable hydrological situation is the fact that the river Supii did not flow at all between Svydovets and Yahotyn. UA-01. Supii valley, area between Vilne and M. Berezanka (Vilne- Berezanka) Aquatic Warbler occupies a part of the floodplain of river Supii, which is a eutrophic sedge marsh. The total area of AW habitat is about 260 ha (Annex 1, Map 1). The data on the water level in the monitoring area in general show a rather sustainable water regime. As a rule, the water level in the monitoring pits ranged from -3 to +12 cm in May and June. In the first 10 years of observation (since 1995), only in one season (June 2003) the water level in the breeding period was low (-5 cm) (Annex 2, Fig. 2). However, since 2011, there have generally been low levels of water in the breeding season. The water level in water point was +2 cm in June 2010, it was -10 cm in the third decade of May 2011, -6 cm – in the first decade of June 2012, -2 cm – in the third decade of June 2013, +2 cm – in the second decade of June 2014, -9 cm – in the first st decade of June 2015, +2 cm – in the first decade of June 2016. In 2017 (1 decade of June), the water level was -20 cm. During the survey the whole breeding area (from the southern to the northern border) was completely dry – the water level was 20-60 cm below the ground (Annex 2, Fig. 2). This is the lowest level of water since 1995. As result in winter and spring most of the AW territory burned out (about 70%). In this season we carried out two evening censuses, which covered the whole breeding site. On the monitoring plot (40 hectares) no AW have been recorded. For comparison, on the same plot in 2016 2 males were registered, in 2015 – 12, in 2014 – 13, in 2013 – 22, and in 2012 – 16. A total of only 2 males was counted in the whole area. The total number of AW of the breeding group has become critically low – only 2 males (in 2016 it was 15-20 males, in 2014-2015 – 70-80 males, in 2013 – 90-100 males, in 2012 – 80-90 males, in 2010 – 140-160 males). It is possible that next year there will be no AW at all. UA-02. Supii valley, area near Novyi Bykiv (Bykiv) The AW group occupies the western half of the Supii river floodplain. The breeding area is about 50 hectares. The highest AW number occurred in 2005 (20-25 males). In 2017 both the water conditions and the state of vegetation were more or less optimal for AW. Due to a natural decrease in the floodplain of the river, the AW habitats at a distance of 100 m from the edge of the marsh were wet. In some places there was open water. The habitats did not burn. Despite this, only 2 males were recorded on the whole territory. In 2016 the estimated number 6 was 14 males, in 2015 – 8-10, in 2014 – 12-15. UA-03. Supii valley, area near Bilotserkivtsi (Bilotserkivtsi) This AW breeding group is located on the western half of the Supii river floodplain, the total area is about 100 ha.