Broedsucces van kustbroedvogels in de Waddenzee : Resultaten 2015-2016 en trends in broedsucces in 2005-2016
Koffijberg, K. ; Cremer, J.S.M. ; Boer, P. de; Nienhuis, J. ; Schekkerman, H. ; Oosterbeek, K. ; Postma, J. - \ 2017
Wageningen : Wettelijke Onderzoekstaken Natuur & Milieu (WOt-technical report 112) - 50
Data have been collected on the breeding success of several characteristic coastal breeding birds in the Wadden Sea each year since 2005. Ten birds species considered representative of specific habitats and food groups are being monitored. The monitoring scheme on breeding success in coastal breeding birds is run as an ‘early warning system’ to follow the reproductive capacity of the bird populations in the Wadden Sea and understand the processes underlying fluctuations in populations. It is a valuable addition to the monitoring of population numbers and is carried out under a trilateral agreement with Germany and Denmark (TMAP). The results from 2015–2016 and an analysis of data series from the period 2005–2016 (sometimes longer) show that several species on average reared too few young to sustain stable population size in many of these years, especially the Eurasian Oystercatcher, Pied Avocet, Common Tern and Arctic Tern, and in recent years also the Black-headed Gull, whose breeding success has significantly declined since 1995. Other species showing a significant decline in breeding success are the Spoonbill and Common Tern. The only species to show any significant improvement in breeding success since 2005 is the Lesser Black-backed Gull
Monitoring van het voor vogels oogstbare voedselaanbod in de kombergingen van het Pinkegat en Zoutkamperlaag
Ens, B.J. ; Krol, J. ; Meer, J. van der; Piening, H. ; Wijsman, J.W.M. ; Schekkerman, H. ; Rappoldt, C. - \ 2015
Nijmegen : Sovon (Sovon-rapport 2015.15) - 54
aardgas - nadelige gevolgen - natura 2000 - kustgebieden - vogels - waddenzee - foerageren - wetlands - groningen - friesland - natural gas - adverse effects - coastal areas - birds - wadden sea - foraging
De gaswinning vanaf de locaties Moddergat, Lauwersoog en Vierhuizen kan effecten hebben op het Natura 2000 gebied Waddenzee. Uit voorzorg vindt de winning plaats volgens het ‘Hand aan de kraan’ principe. In dat kader vindt een uitgebreide monitoring plaats van biotische en abiotische parameters, om te controleren of gaswinning vanaf de bovengenoemde locaties geen meetbaar nadelig effect heeft op de instandhoudingsdoelstellingen van de speciale beschermingzone Waddenzee, waaronder een groot aantal vogelsoorten waarvoor het gebied is aangewezen.
Site-specific dynamics in remnant populations of Northern Wheatears Oenanthe oenanthe in the Netherlands
Oosten, H.H. van; Turnhout, C. van; Hallmann, C.A. ; Majoor, F. ; Roodbergen, M. ; Schekkerman, H. ; Versluijs, R. ; Waasdorp, S. ; Siepel, H. - \ 2015
Ibis 157 (2015)1. - ISSN 0019-1019 - p. 91 - 102.
spatial synchrony - environmental correlation - scale - dispersal - birds - immigration - landscape - density - impact - space
Dynamics of populations may be synchronized at large spatial scales, indicating driving forces acting beyond local scales, but may also vary locally as a result of site-specific conditions. Conservation measures for fragmented and declining populations may need to address such local effects to avoid local extinction before measures at large spatial scales become effective. To assess differences in local population dynamics, we aimed to determine the demographic drivers controlling population trends in three remaining populations of the Northern Wheatear Oenanthe oenanthe in the Netherlands, as a basis for conservation actions. An integrated population model (IPM) was fitted to field data collected in each site in 2007–2011 to estimate fecundity, survival and immigration. Sites were 40–120 km apart, yet first-year recruits were observed to move between some of the sites, albeit rarely. All three populations were equally sensitive to changes in fecundity and first-year survival. One population was less sensitive to adult survival but more sensitive to immigration. A life table response experiment suggested that differences in immigration were important determinants of differences in population growth between sites. Given the importance of immigration for local dynamics along with high philopatry, resulting in low exchange between sites, creating a metapopulation structure by improving connectivity and the protection of local populations are important for the conservation of these populations. Site-specific conservation actions will therefore be efficient and, for the short term, we propose different site-specific conservation actions.
Shorebird incubation behviour and its influence on the risk of nest predation
Smith, P.A. ; Tulp, I.Y.M. ; Schekkerman, H. ; Gilchrist, H.G. ; Forbes, M.R. - \ 2012
Animal Behaviour 84 (2012)4. - ISSN 0003-3472 - p. 835 - 842.
daily energy-expenditure - site selection - parent birds - sandpipers - defense - pigmentation - patterns - habitat - success - waders
Both nest survival and incubation behaviour are highly variable among shorebirds (Charadrii), and we tested whether more conspicuous incubation behaviour increased the risk of nest predation. During 2000-2006, we monitored nest fate at 901 shorebird nests at three study sites across the circumpolar Arctic. Using miniature video recorders and nest temperature sensors, we obtained 782 days of behavioural data for 161 nests of 11 species. We related nest fate to the rate and duration of adults' nest absences or restless movements on the nest, as well as the total proportion of each day that adult birds engaged in these activities. Nest predation was positively related to the proportion of time that each species left the nest unattended. After controlling for species effects, the likelihood of a successful nesting attempt was lower for individuals that spent more time off the nest, but among failed nests, the number of days that a nest survived prior to depredation was not significantly predicted by measures of incubation behaviour. To control for weather or seasonal effects, we paired observations from nests that were ultimately depredated with observations from successful nests of the same species on the same day. In this paired sample (dominated by two species: red phalaropes, Phalaropus fulicarius, and little stints, Calidris minuta), both incubation recesses and restless movements were more numerous among failed versus successful nests. Our results suggest that more conspicuous incubation behaviour is indeed related to a higher risk of nest predation, and that this relationship may underlie patterns of nest survival within and among shorebird species. (C) 2012 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
Eggs in the Freezer: energetic Consequences of Nest Site and Nest Design in Arctic Breeding Shorebirds
Tulp, I.Y.M. ; Schekkerman, H. ; Leeuw, J.J. de - \ 2012
PLoS ONE 7 (2012)6. - ISSN 1932-6203 - 9 p.
mating system - heat-loss - incubation - predation - expenditure - insulation - sandpipers - selection - clutch - tundra
Birds construct nests for several reasons. For species that breed in the Arctic, the insulative properties of nests are very important. Incubation is costly there and due to an increasing surface to volume ratio, more so in smaller species. Small species are therefore more likely to place their nests in thermally favourable microhabitats and/or to invest more in nest insulation than large species. To test this hypothesis, we examined characteristics of nests of six Arctic breeding shorebird species. All species chose thermally favourable nesting sites in a higher proportion than expected on the basis of habitat availability. Site choice did not differ between species. Depth to frozen ground, measured near the nests, decreased in the course of the season at similar non-species-specific speeds, but this depth increased with species size. Nest cup depth and nest scrape depth (nest cup without the lining) were unrelated to body mass (we applied an exponent of 0.73, to account for metabolic activity of the differently sized species). Cup depth divided by diameter2 was used as a measure of nest cup shape. Small species had narrow and deep nests, while large species had wide shallow nests. The thickness of nest lining varied between 0.1 cm and 7.6 cm, and decreased significantly with body mass. We reconstruct the combined effect of different nest properties on the egg cooling coefficient using previously published quantitative relationships. The predicted effect of nest cup depth and lining depth on heat loss to the frozen ground did not correlate with body mass, but the sheltering effect of nest cup diameter against wind and the effects of lining material on the cooling coefficient increased with body mass. Our results suggest that small arctic shorebirds invest more in the insulation of their nests than large species
Do Uniparental Sanderlings Calidris alba Increase Egg Heat Input to Compensate for Low Nest Attentiveness?
Reneerkens, J. ; Grond, K. ; Schekkerman, H. ; Tulp, I.Y.M. ; Piersma, Th. - \ 2011
PLoS ONE 6 (2011)2. - ISSN 1932-6203 - 9 p.
daily energy-expenditure - incubation schedules - avian embryos - tree swallows - clutch size - wood ducks - temperature - behavior - demands - birds
Birds breeding in cold environments regularly have to interrupt incubation to forage, causing a trade-off between two mutually exclusive behaviours. Earlier studies showed that uniparental Arctic sandpipers overall spend less time incubating their eggs than biparental species, but interspecific differences in size and ecology were potential confounding factors. This study reports on a within-species comparison of breeding schedules and metal egg temperatures in uni- and biparental sanderlings (Calidris alba) in Northeast Greenland in relation to ambient temperature. We recorded incubation schedules with nest temperature loggers in 34 sanderling clutches (13 uniparentals, 21 biparentals). The temperature of a metal egg placed within the clutch of 17 incubating birds (6 uniparentals, 9 biparentals) was measured as an indicator of the heat put into eggs. Recess frequency, recess duration and total recess time were higher in uniparentals than in biparentals and positively correlated with ambient temperatures in uniparentals only. Uniparental sanderlings maintained significantly higher metal egg temperatures during incubation than biparentals (1.4°C difference on average). Our results suggest that uniparental sanderlings compensate for the lower nest attendance, which may prolong the duration of the incubation period and negatively affect the condition of the hatchlings, by maintaining a higher heat flux into the eggs.
Broedsucces van kustbroedvogels in de Waddenzee in 2007 en 2008
Kleunen, A. van; Koffijberg, K. ; Boer, P. ; Nienhuis, J. ; Camphuysen, C.J. ; Schekkerman, H. ; Oosterbeek, K.H. ; Jong, M.L. de; Ens, B.J. ; Smit, C.J. - \ 2010
Wageningen : Wettelijke Onderzoekstaken Natuur & Milieu (WOt-werkdocument 227) - 73
broedvogels - watervogels - voortplantingsvermogen - kustgebieden - monitoring - populatiedynamica - waddenzee - breeding birds - waterfowl - reproductive performance - coastal areas - monitoring - population dynamics - wadden sea
Voor het derde en vierde opeenvolgende jaar werd het broedsucces van een aantal kustbroedvogels in de Waddenzee bepaald. Van Eider, Scholekster, Kluut, Kokmeeuw, Zilvermeeuw en Visdief, alsmede van Kleine Mantelmeeuw en Noordse Stern werd informatie verzamelen over het nestsucces en uitvliegsucces (het uiteindelijke broedsucces). Kennis over de jaarlijkse variatie in broedresultaten bij de verschillende soorten is van belang als een early warning systeem om de 'kwaliteit' (het reproducerend vermogen) van de vogelpopulaties in de Waddenzee te volgen en de achterliggende processen van populatieveranderingen te doorgronden. Directe aanleiding voor het project vormde de evaluatie van de effectiviteit van het nieuwe schelpdiervisserijbeleid en de mogelijke gevolgen voor de voedselvoorziening van schelpdieretende vogels.
Effect van nestbezoek en onderzoek op weidevogels
Goedhart, P.W. ; Teunissen, W.A. ; Schekkerman, H. - \ 2010
Wageningen : Wageningen Universiteit (SOVON-onderzoeksrapport 2010/01) - 84
weidevogels - natuurbescherming - cost effective analysis - ecologische modellering - beslissingsmodellen - grassland birds - nature conservation - cost effectiveness analysis - ecological modeling - decision models
In Nederland wordt veel energie gestoken in het zoeken en beschermen van weidevogellegsels tegen agrarische activiteiten om zo de gestage achteruitgang van weidevogels te stoppen. Jaarlijks betreft dit zo’n 150.000 nesten. Er is echter discussie ontstaan over het positieve effect van dit soort beschermingsmaatregelen omdat het controleren van nesten tot een verhoging van de verliezen zou kunnen leiden; het zogenaamde bezoekeffect. Om dit vast te kunnen stellen is allereerst gezocht naar een berekeningswijze waarmee een eventueel bezoekeffect kan worden aangetoond. Hiervoor zijn in totaal drie verschillende modellen ontwikkeld en getest. De verschillende modellen zijn uitgetest met een gesimuleerde dataset waarin de waarden voor de dagelijkse overlevingskans en het bezoekeffect bekend zijn. De beste schattingen van het bezoekeffect en de dagelijkse overlevingskans worden behaald met een model waarin tevens de broedduur en de eerste eilegdatum zijn gemodelleerd.
Wat kost het behoud van onze akkervogels?
Bos, J.F.F.P. ; Sierdsema, H. ; Schekkerman, H. ; Scharenburg, C.W.M. - \ 2010
De Levende Natuur 111 (2010)6. - ISSN 0024-1520 - p. 259 - 263.
vogels - bouwland - gemeenschappelijk landbouwbeleid - kosten - agrarisch natuurbeheer - birds - arable land - cap - costs - agri-environment schemes
Het Planbureau voor de Leefomgeving wilde weten welke maatregelen in de Nederlandse landbouw nodig zijn om akkervogeldoelen te halen en wat deze maatregelen kosten. In het rapport "Een veldleeuwerik zingt niet voor niets!" zijn deze vragen beantwoord. Dit artikel geeft de belangrijkste bevindingen.
Adverse effectsof agricultaral intensification and climate change on breeding habitat quality of Blacktailed Godwits Limosa l. limosa in the Netherlands
Kleijn, D. ; Schekkerman, H. ; Dimmers, W.J. ; Kats, R.J.M. van; Melman, T.C.P. ; Teunissen, W.A. - \ 2010
Ibis 152 (2010)3. - ISSN 0019-1019 - p. 475 - 486.
farmland bird populations - lapwing vanellus-vanellus - agri-environment schemes - grassland management - chicks - eggs - biodiversity - intensity - britain - europe
Agricultural intensification is one of the main drivers of farmland bird declines, but effects on birds may be confounded with those of climate change. Here we examine the effects of intensification and climate change on a grassland breeding wader, the Black-tailed Godwit Limosa l. limosa, in the Netherlands. Population decline has been linked to poor chick survival which, in turn, has been linked to available foraging habitat. Foraging habitat of the nidifugous chicks consists of uncut grasslands that provide cover and arthropod prey. Conservation measures such as agri-environment schemes aim to increase the availability of chick foraging habitat but have not yet been successful in halting the decline. Field observations show that since the early 1980s, farmers advanced their first seasonal mowing or grazing date by 15 days, whereas Godwits did not advance their hatching date. Ringing data indicate that between 1945 and 1975 hatching dates advanced by about 2 weeks in parallel with the advancement of median mowing dates. Surprisingly, temperature sums at median mowing and hatching dates suggest that while the agricultural advancement before 1980 was largely due to agricultural intensification, after 1980 it was largely due to climate change. Examining arthropod abundance in a range of differently managed grasslands revealed that chick food abundance was little affected but that food accessibility in intensively used tall swards may be problematic for chicks. Our results suggest that, compared with 25 years ago, nowadays (1) a much higher proportion of clutches and chicks are exposed to agricultural activities, (2) there is little foraging habitat left when chicks hatch and (3) because of climate change, the vegetation in the remaining foraging habitat is taller and denser and therefore of lower quality. This indicates that for agri-environment schemes to make a difference, they should not only be implemented in a larger percentage of the breeding area than the current maxima of 20–30% but they should also include measures that create more open, accessible swards
Een veldleeuwerik zingt niet voor niets! : schatting van kosten van maatregelen voor akkervogels in de context van een veranderend gemeenschappelijk landbouwbeleid
Bos, J.F.F.P. ; Sierdsma, H. ; Schekkerman, H. ; Scharenburg, C.W.M. - \ 2010
Wageningen : Wettelijke Onderzoekstaken Natuur & Milieu (WOt-rapport 107) - 242
vogels - gemeenschappelijk landbouwbeleid - akkerbouw - kosten - agrarisch natuurbeheer - birds - cap - arable farming - costs - agri-environment schemes
Als gevolg van intensivering en schaalvergroting nemen de aan landbouw gebonden vogelsoorten op Europese schaal zowel in aantal als verspreiding af. Door hun verbondenheid met landbouw is het lot van akkervogels nauw gerelateerd aan de effecten van het Europese Gemeenschappelijk Landbouwbeleid (GLB). Afhankelijk van de uitwerking van dit GLB na 2013 neemt de betekenis van gerichte betalingen aan de landbouw voor specifieke doelen, waaronder biodiversiteit, mogelijk toe. Binnen de context van een veranderend GLB enerzijds en biodiversiteitsdoelstellingen voor akkervogels anderzijds, verschaft dit rapport inzicht in de (kosten van) maatregelen die in de Nederlandse landbouw op landelijk niveau nodig zijn om biodiversiteitsdoelstellingen voor akkervogels te behalen. Alle maatregelen richten zich op het voorzien in de ‘grote drie’ voor akkervogels: broedgelegenheid en dekking, voldoende aanbod van toegankelijk zomervoedsel (insectenrijke habitats in nabijheid van nest) en voldoende aanbod van wintervoedsel (graankorrels, onkruidzaden). De geschatte kosten van de maatregelen bedragen minimaal enkele tientallen miljoenen tot maximaal €176 miljoen. Trefwoorden: akkervogels, agrarisch natuurbeheer, Gemeenschappelijk landbouwbeleid, biodiversiteit
Mortality of Black-tailed Godwit Limosa limosa and Northern Lapwing Vanellus vanellus chicks in wet grasslands: influence of predation and agriculture
Schekkerman, H. ; Teunissen, W. ; Oosterveld, E. - \ 2009
Journal of Ornithology 150 (2009)1. - ISSN 2193-7192 - p. 133 - 145.
curlew numenius-arquata - breeding success - duckling survival - pheasant chicks - population - management - birds - brood - parameters - abundance
Grassland-breeding shorebirds show widespread declines due to a reduction in breeding productivity following agricultural intensification. However, there is also concern that increasing predation causes further declines or precludes population recovery. Predation may itself be enhanced by agriculture through changes in habitat or food availability, but little is known about the mortality of nidifugous shorebird chicks. We studied mortality by radio-tagging 662 chicks of Black-tailed Godwit Limosa limosa and Northern Lapwing Vanellus vanellus in 15 farmland sites in the Netherlands. Tagging and handling had no effect on the condition and survival of godwit chicks, but body condition was reduced by 6-11% in lapwing chicks wearing a tag for longer than 3 days. Fledging success was 0 - 24% in both species. Mortality was highest in young chicks but remained considerable until after fledging. Losses were traced mostly to predators (70 - 85%; 15 species, predominantly birds), but at least 5 - 10% were due to mowing, and 10 - 20% were due to other causes, including entrapment in ditches and starvation. Chicks staying in fields that were cut before the next radio check were found much more often as mowing victims and somewhat more often as prey remains than chicks in fields not cut, indicating that predation includes a limited amount of scavenging. The predation hazard for godwit chicks was higher in recently cut or grazed fields than in the tall, uncut grasslands they preferred, while that for lapwing chicks was lowest in grazed fields. In godwit chicks, poor body condition increased mortality risk, not only from starvation but also from other causes. Predation on godwit chicks was thus enhanced by intensive farming through a decline in the availability of cover, augmented by a reduced body condition, possibly due to food availability problems. Changes in farming practice may therefore help reduce predation pressure, though the observed interactions explained only part of the high predation rate in godwits and none in lapwings. Predator abundance has increased in Dutch wet grassland regions, and chick predation has become a factor that should be considered in planning the type and location of conservation measures.
Do meadow birds profit from agri-environment schemes in Dutch agricultural landscapes?
Breeuwer, A.J.G. ; Berendse, F. ; Willems, F. ; Foppen, R. ; Teunissen, W. ; Schekkerman, H. ; Goedhart, P.W. - \ 2009
Biological Conservation 142 (2009)12. - ISSN 0006-3207 - p. 2949 - 2953.
godwit limosa-limosa - farmland - biodiversity - intensification - management - abundance - success
Since 1992 the European Union helps member states to reverse the loss of biodiversity in agricultural landscapes by the financial support of agri-environment schemes. Long-term studies investigating the effects of these schemes are an essential prerequisite for the development of an effective policy to restore biodiversity on farmland. In Dutch meadow landscapes almost all agri-environment schemes focus on the restoration of meadow bird populations by postponement of the mowing date. Between 1990 and 2002 we measured long-term changes in meadow bird densities in areas with and without agri-environment schemes in the Netherlands, both before and after the start of the contract. During these years bird territories were surveyed during five field visits between 15 March and 15 June. Densities of black-tailed godwit (Limosa limosa), and redshank (Tringa totanus) were higher in the areas with management agreements, but these differences were already present before the start of the contracts. After the start of the management contracts densities of black-tailed godwit and oystercatcher (Haematopus ostralegus) did not increase, while those of lapwing (Vanellus vanellus) and redshank even declined relative to the control areas. It is concluded that the current agri-environment schemes are not sufficient to restore meadow bird populations in Dutch agricultural landscapes. In addition to the prescribed postponement of the mowing date, it is probably necessary to raise groundwater levels and to reduce fertilization to allow for the development of an open vegetation structure that will increase chick survival to sufficiently high levels
Body condition of shorebirds upon arrival at their Siberian breeding grounds
Tulp, I.Y.M. ; Schekkerman, H. ; Klaassen, R.H.G. ; Ens, B.J. ; Visser, G.H. - \ 2009
Polar Biology 32 (2009)3. - ISSN 0722-4060 - p. 481 - 491.
calidris-canutus-islandica - red knots - energy-expenditure - tundra arthropods - ellesmere-island - fat reserves - migration - stores - survival - waders
Abstract Arctic breeding shorebirds carry substantial body stores on their long-distance migrations from their non-breeding grounds. Upon arrival at the breeding area the remains of these stores can be used for egg formation, insurance against poor feeding conditions or rebuilding organs. We quantified body condition (body mass, total body water, lean body mass and fat mass estimated using the deuterium dilution method) in seven shorebird species caught upon arrival in the Siberian Arctic. Arrival condition was compared with incubation condition in a subset of species. After correction for structural size, body mass was significantly lower at arrival than during incubation in most of the species (but 3¿18% above lean mass). Fat index (fat mass/lean mass) varied between 5.1 and 13.2%. Fat stores were estimated to enable survival for 0.6 days for the smallest and 2.5 days for the largest species. We discuss possible functions of arrival stores: insurance, egg-formation or rebuilding organs.
Energetic demands during incubation and chick rearing in a uniparental and a biparental shorebird breeding in the high Arctic
Tulp, I.Y.M. ; Schekkerman, H. ; Bruinzeel, L. ; Jukema, J. ; Visser, G.H. ; Piersma, T. - \ 2009
The Auk : a quarterly journal of ornithology 126 (2009)1. - ISSN 0004-8038 - p. 155 - 164.
labeled water method - temperature regulation - expenditure - birds - allocation - waders - reproduction - validation - sandpipers - patterns
Rearing of young has long been considered the energetically most demanding phase of the avian breeding cycle. Arctic-breeding shorebirds expend large amounts of energy during breeding. Because they are too small to carry sufficient stores to sit out the incubation period, they regularly interrupt incubation to feed and still can run short of energy, particularly in species in which one adult takes care of the eggs and chicks alone (uniparental). We measured daily energy expenditure (DEE) and time budgets during incubation and chick rearing in the smallest uniparental Arctic shorebird, the Little Stint (Calidris minuta). Daily energy expenditure decreased with increasing temperature but did not differ between the incubation and chick-rearing periods. Because of the increase in potential foraging time from incubation to the chick-rearing phase, the foraging intake rate required to balance the budget dropped by two-thirds. To evaluate the effect of uniparental care on energy budgets, we also measured DEE in the Dunlin (C. alpina), a sympatric congener in which both parents incubate but the female deserts the brood after hatching. Daily energy expenditure decreased with temperature, was the same during incubation and chick rearing, and was higher in males. Our results are discussed in relation to the timing of breeding of Arctic shorebirds with different systems of parental care. Received 31 October 2007, accepted 28 September 2008.
The effect of 'mosaic management' on the demography of black-tailed godwit Limosa limosa on farmland
Schekkerman, H. ; Teunissen, W. ; Oosterveld, E. - \ 2008
Journal of Applied Ecology 45 (2008)4. - ISSN 0021-8901 - p. 1067 - 1075.
agri-environment schemes - bird populations - agricultural intensification - food resources - success - chicks - biodiversity - netherlands - grasslands - survival
1. Like many farmland birds, the largest European population of the black-tailed godwit Limosa limosa, in The Netherlands, has been declining for decades despite conservation measures including agri-environment schemes (AES). In a new experimental AES aiming to reverse this decline, collectives of farmers implemented spatially coordinated site-level habitat management ('mosaic management') including delayed and staggered mowing of fields, refuge strips and active nest protection. 2. We evaluated the effectiveness of mosaic management by measuring godwit breeding success in six experimental sites and paired controls. Productivity was higher in mosaics than in controls due to fewer agricultural nest losses. Chick fledging success was poor in both treatments. Productivity compensated for adult mortality in only one AES site. 3. Although creating chick habitat was a major management goal, the availability of tall grass during the fledging period did not differ between treatments, mainly because rainfall delayed mowing in all sites and study years. However, chick survival increased with the availability of tall grass among sites. Higher chick survival will thus enhance the positive effect of mosaic management in drier years, but sensitivity to weather represents a weakness of the AES design. 4. Available estimates of productivity in Dutch godwits suggest a strong reduction over the past 20 years and implicate chick survival as the main driver of their decline. Earlier mowing of grassland is the main causal mechanism, but changes in vegetation structure and composition, and increased predation may also have contributed. 5. Synthesis and applications. Demographic rates like breeding success are useful parameters for evaluating effects of management. Mosaic management increases the productivity of black-tailed godwits, but does not ensure long-term population viability for this flagship species of wet grassland bird communities. More stringent management prescriptions need to improve both the area and the quality (vegetation structure) of grassland mown late. Management efforts should be concentrated in areas with favourable pre-conditions in order to improve overall effectiveness.
Identifying predators of eggs and chicks of Lapwing Vanellus vanellus and Black-tailed Godwit Limosa limosa in the Netherlands and the importance of predation on wader reproductive output
Teunissen, W. ; Schekkerman, H. ; Willems, F. ; Majoor, F. - \ 2008
Ibis 150 (2008)Suppl. 1. - ISSN 0019-1019 - p. 74 - 85.
crow predation - nest-predation - success - population - management - farmland - grasslands - survival - britain - birds
Farmland bird populations in the Netherlands have shown an accelerating decline in recent years, despite extensive conservation efforts including reserves, agri-environment schemes and protection of nests by volunteers. Although agricultural intensification is the main cause underlying these declines, there is a growing concern that the ongoing decline of grassland-breeding shorebirds in recent years is caused or aggravated by increasing predation. Although Red Fox Vulpes vulpes and Carrion Crow Corvus corone are often accused of causing widespread breeding losses, and calls for management of these species are made, very few field data are available on the incidence of predation on grassland shorebirds and the relative importance of different predators. To obtain such data, we identified egg predators using temperature loggers and continuous video recordings of 792 clutches, and chick predators by radiotagging 662 chicks of Black-tailed Godwit Limosa limosa and Northern Lapwing Vanellus vanellus. In total, 22 species were identified as predators of eggs or chicks, of which Red Fox, Common Buzzard Buteo buteo, Grey Heron Ardea cinerea and Stoat Mustela erminea were the most frequent. Eggs were taken primarily by mammals and chicks more often by birds. There was great variation in predation levels and species involved in predation of clutches between sites and years, but less in chick predation. Hence, there was no correlation between predation levels on clutches and those on chicks within the same sites. In sites where more then 50% of clutches were lost to predation, however, nocturnal predators took the larger share. As temporal and spatial variation on a small scale significantly influences predation levels, a site-specific approach based on sound knowledge of the local situation will be more effective in reducing predation on farmland birds than general, country-wide measures. Calculations based on our data indicate that eliminating only one loss factor at a time will often not reverse a local population decline, and provide a strong argument for targeting several locally limiting factors simultaneously instead of focusing on mitigation of predation alone.
Factoren die de overleving van weidevogelkuikens beïnvloeden
Teunissen, W. ; Klok, T.C. ; Kleijn, D. ; Schekkerman, H. - \ 2008
Ede : Directie Kennis, Ministerie van Landbouw, Natuur en Voedselkwaliteit (SOVON nr. 2008/01) - 80
vogels - onvolwassenheid - overleving - dierecologie - monitoring - weidevogels - agrarisch natuurbeheer - birds - juvenility - survival - animal ecology - monitoring - grassland birds - agri-environment schemes
Uit onderzoek naar de effectiviteit van het huidige weidevogelbeheer komt telkens naar voren dat er voor de ontwikkeling van een beter beheer op een aantal punten nog onvoldoende kennis aanwezig is over factoren die van belang zijn voor de overleving van weidevogelkuikens. Die ontbrekende kennis spitst zich toe op de invloed die weer, voedsel en beheer op de conditie en daarmee op de overleving van kuikens hebben. Een deel van de vragen kan alleen worden beantwoord door nieuw opgezet veldwerk, maar een deel kan wel beantwoord worden op grond van nieuwe analyses en bestaande datasets . De belangrijkste uitkomsten van die analyses worden hieronder beschreven.
The ongoing decline of the breeding population of Black-tailed Godwits Limosa l. limosa in The Netherlands is not explained by changes in adult survival
Roodbergen, M. ; Klok, C. ; Schekkerman, H. - \ 2008
Ardea 96 (2008)2. - ISSN 0373-2266 - p. 207 - 218.
redshank tringa-totanus - west-african rainfall - warblers acrocephalus-schoenobaenus - stork ciconia-ciconia - natal dispersal - site fidelity - purple heron - rates - drought - consequences
The Black-tailed Godwit Limosa limosa is a characteristic breeding wader of wet grasslands in the Netherlands which has suffered a strong population decline since the 1960s. Low breeding success has been implicated as the main driver of this decline and here we examine whether changes in adult survival could also have played a role. Adult godwits were colour-ringed and resighted from 2002 through 2005 at four study sites in the Netherlands. Apparent adult survival was estimated in program MARK using Burnham¿s model for both live resightings and dead recoveries. In addition, nest site fidelity was estimated at two of the sites by recording the distance between nest locations in successive years. Apparent adult survival was 0.93 (SE 0.03) in one study area and 0.81 (SE 0.04) in the other three sites. Overall apparent adult survival was 0.83 (SE 0.03). These values are similar to estimates from the 1970s and 1980s. Nest site fidelity was higher in the site with highest survival (median distance between nests in successive years: 49 m vs. 252 m in the other site), suggesting that the difference in apparent survival may result from differences in emigration rates. Thus, our results suggest that current adult survival is not different from rates 30 years ago, and therefore do not point to reduced adult survival as the driver behind the current population decline of Black-tailed Godwits.
Ecologische kenmerken van weidevogeljongen en de invloed van beheer op overleving. Kennisoverzicht en effectiviteit van maatregelen
Oosterveld, E.B. ; Kleijn, D. ; Schekkerman, H. - \ 2008
Ede : Directie Kennis, Ministerie van Landbouw, Natuur en Voedselkwaliteit (Rapport / DK nr. 2008/090) - 72
vogels - onvolwassenheid - overleving - dierecologie - weidevogels - birds - juvenility - survival - animal ecology - grassland birds
Rapport over de effectiviteit van beheersmaatregelen voor overleving van primaire weidevogelkuikens in graslanden, op basis van wetenschappelijke en niet-wetenschappelijke literatuur. Per sprake komen: Ecoprofielen weidevogeljongen van: Kievit (Vanellus vanellus); Grutto (Limosa limosa); Tureluur (Tringa totanus); Scholekster (Haematopus ostralegus); Watersnip (Gallinago gallinago); Kemphaan (Philomachus pugnax); Slobeend (Anas clypeata); Zomertaling (Anas querquedula); Kuifeend (Aythya fuligula); Veldleeuwerik (Alauda arvensis); Graspieper (Anthus pratensis); Gele kwikstaart (Motacilla flava)