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Nesting phenologies of northern flickers and European starlings in central British Columbia, 1 May=day 121. Sample is 350 nests from 1999–2001. Dark bars are first nests and light bars are known second nesting attempts by flickers. The date of the latest starling initiation date is shown by the dashed line, and an arrow marks the latest observed eviction by starlings.
Source publication
European starlings (Sturnus vulgaris) introduced to North America compete with native cavity-nesting birds for nest sites. I examined whether natural selection could favour a strategy of delayed nesting in a population of northern flickers (Colaptes auratus), a native woodpecker, to reduce overlap in breeding phenology with starling competitors. I...
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Context 1
... 1998, both flickers and starlings arrived on the study area after spring migration nearly syn- chronously, around 20 April (K. Wiebe, unpubl.). However, starlings initiated egg-laying 3 -7 days be- fore the first flickers and continued to initiate clutches up to 22 June, overlapping nearly the entire laying period of flickers ( Fig. 1). Over four years, evictions by starlings varied from 4.1% in 2000 (n= 97 nests), to 9.1% 1999 (n =88). There were no differences in the proportion of nests evicted among years (x 2 6 = 3.13, n =365, P=0.79) and the overall percent of evictions was 6.9%. Evictions usually occurred during the egg-laying period or during incubation, but ...
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... nests in the same area were taken by starlings during 1994-96 (Ingold 1998). Higher rates of eviction in the latter study may have been confounded by the experi- mental placement of nest boxes beside flicker cavities (Ingold 1998). Interestingly, probability of eviction in the latter study declined from about 75% early in the season to nearly 0% (Fig. 2 in Ingold 1998) which seems to be the threshold degree of competition to favour delayed nesting (Fig. 6, bottom). However, it is still unclear whether such intense competition is present in flicker populations without nest boxes. In comparison, red-bellied woodpeckers, behaviourally less aggressive than flickers, suffered a 52% nest loss to starlings ...
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... and Eadie 1999). At northern latitudes where breeding seasons are short, delayed reproduction is a less viable option than at more southerly locales. Starlings were the earliest cavity nesters within the nest-web communtiy in central British Columbia and their breeding season overlapped the entire time span of first nest attempts by flickers (Fig. 1). There were no overt agonistic encounters between flickers and other woodpecker species over nest sites, but agonistic interactions were observed with American kestrels (Falco spar6erius) and tree swallows (Tachycineta bicolor) which tended to nest later than flickers (pers. obs.). Therefore, delaying reproduction to escape ...
Citations
... Many investigations have shown that nest-predation rates decrease [13,[18][19][20][21][22][23][24][25] or increase during the breeding season [26][27][28][29][30][31][32][33][34]. Other investigations have found that they Diversity 2024, 16, 356 3 of 16 result implies that predation rates are highest in the middle of the breeding season. ...
Investigations of seasonal variations in nest predation rates yield highly variable results. Some investigations argue that search image is responsible for some of the nest-predation patterns, but as far as we know, this study is the first in which search image in connection with seasonal variation in nest-predation rate has been experimentally tested. We used 1457 artificial nests placed in an identical way during the months of March to August, either in the two months consecutively or early and late within one of the two months, between the years 2000 and 2023. In addition, we compared the change in nest-predation rates at 113 artificial and 460 natural nests between the same two months. We estimated the seasonal variation in the abundance of breeding birds in the study area with 140 point counts to find the abundance of different species at the times when they normally breed. We found a strong and consistent seasonal variation in the nest-predation rate, with the highest predation rate in the middle of the breeding season. There was a similar change in the predation rate on natural and artificial nests between May and June. From July to August, the predation rate on artificial nests decreased significantly, while the search-image experiment revealed a significant increase between the same two months. A generalized linear mixed-effect model analysis found that the variation in nest-predation rates on artificial nests was significantly affected by seasonal variation in the estimated number of natural nests, that nests in trees were predated more often than nests on the ground, and that nests in the open landscape and on forest edges suffered higher predation rates than nests inside a forest. Mammals were nest predators significantly more often inside forests and on forest edges than in the open landscape, but birds were much more common nest predators than mammals independent of placement and habitat. Our experiment shows that search image explains the seasonal variation in nest-predation rates. However, more investigations are needed to find the reasons for the variation in published results on seasonal variation. Further, experimental testing on search image to find its contribution to the seasonal variation in nest-predation rates in other areas is also needed.
... Furthermore, starlings may also overcome cavity availability limitation because they have proven to be considerably successful cavity usurpers through aggressive behaviors (Frei et al. 2015 andJauregui et al. 2021 and articles there cited). Starlings usurping cavities of native species would delay nest initiation dates of the latter, which could decrease their nesting success and re-nesting probability (Wiebe 2003). Nest success of native birds is considerably reduced by the end of the season at these latitudes, probably due to an increase in predator activity (Segura and Reboreda 2012, Jauregui 2020) and higher ectoparasite incidence (Segura and Palacio 2021). ...
Invasive species present numerous threats to ecosystems as they compete with other species for resources and displace them from their habitats. One of the most invasive birds is the European Starling (Sturnus vulgaris), which recently invaded and started to expand throughout South America. Despite its negative impacts on the South American native fauna, there is no information on its breeding success, the factors affecting it, and its population recruitment rate. We monitored 100 European Starling nests in a native forest of central-eastern Argentina during the 2020-2021 and 2021-2022 breeding seasons. We estimated breeding parameters for the population (clutch size, number of fledglings, nest survival, among others) and measured nest-site features at different spatial scales to assess if they influenced nest survival and productivity. Starlings started breeding earlier than native species, used three cavity types (natural, woodpecker, and Rufous Hornero, Furnarius rufus), produced ~3 fledglings per successful nest, and had a 38% estimated nest success probability. Daily survival rates were negatively related to nest-tree diameter at breast height (DBH) but not related to landscape features. Nest survival and productivity were higher than those of native cavity-nesting birds. Moreover, starling successful occupancy of cavities earlier in the season may delay native cavity-nesting birds nest initiation dates, which negatively affects their breeding success. The inverse relationship between DBH and nest survival could indicate preservation of mature trees may help to reduce nest success rate but such a relationship deserves further study. The high reproductive rates in our study and effective nest usurpation by starlings shown elsewhere suggests that the effect of starlings on endangered native species needs further study and starlings may need to be controlled.
... 0.42 g/cm 3 , see 50], but the investment could be considerably higher in forests without this condition. Second, the constant interruptions of breeding attempts delayed the initiation date of reproduction for the Green-barred Woodpecker pair, which had at least two consequences: 1) as the breeding season progresses, the probability that woodpeckers will make new nesting attempts decreases [51] and 2) at these latitudes, the nest success rate decreases as the season progresses [52-54, AJ, unpubl. data], because of a higher rate of nest predation or seasonal variation in food availability [30]. ...
The European Starling (Sturnus vulgaris) is a cavity-nesting bird with great invasive potential. As a result of human intervention, this bird is now distributed across all continents (except Antarctica) and its distribution range is increasing at an alarming rate. The European Starling was introduced to Argentina in 1983 and is currently distributed across almost the entire country. It is considered one of the hundred most damaging invasive species in the world and constitutes a serious competitive threat to native cavity-nesting birds. Interactions between European Starlings and cavity-nesting birds generally have negative consequences on native bird populations, although there are still few reports in the literature that account for the degree of damage. In this study, we report for the first time details of the harassment strategy and subsequent cavity usurpation by European Starlings on a breeding pair of Green-barred Woodpeckers (Colaptes melanochloros) in an urban area of central-eastern Argentina. Over one breeding season, the woodpeckers excavated seven cavities, none of which were successful. In six of these reproductive attempts (86%) we recorded interactions with European Starlings and in five (71%) the cavity was usurped. On three occasions we recorded a cooperative harassment strategy by a group of European Starlings causing the woodpeckers to abandon the cavity. Our report is especially relevant if we consider the invasive potential of the European Starling worldwide and the frequently limited cavity supply in bird breeding habitats. Therefore, we encourage governmental authorities and environmental NGOs to take measures to control the populations of this aggressive invasive species.
... This is considered an anti-predation behaviour, where woodpeckers move to and occupy new sites every year (Sonerud 1985;Hagvar et al. 1990;Mazgajski 2002a). Newly excavated cavities have the advantage of being unavailable early in the spring, which avoids their occupation by competing cavity-nesting species (Wiebe 2003). Moreover, the nesting limb with old cavities can fall apart, cavities can be filled with water or used by other cavity-nesting species (Koenig et al. 2021). ...
Abstract
Levaillant’s Woodpecker is an endemic species of the forests of north-western Africa. Through the cavities it digs, its presence is essential for the existence of other cavity nesters. However, despite its importance to its ecosystems, there are not much data dealing with its ecology and especially its habitats. To describe these habitats, we investigated nest-sites characteristics of Levaillant’s Woodpecker Picus vaillantii in the Aures forest massifs of north-eastern Algeria, during two breeding seasons 2018 and 2019. Using the point count method, we detected 45 occupied nesting cavities, unevenly distributed over the formations, dominated by Atlas cedar (73.3%), Holm oak (13.3%), and Aleppo pine (4.4%). Results showed high utilisation of live trees (71.1%) with healthy crowns (75.5%). Findings also revealed that the species favoured tree trunks (77.7%) as nesting support and that the determination of the nest height was strongly dependent on the height of the nesting tree. Nest height and tree diameter at this height varied significantly among tree species. Nests were higher in Aleppo pine, however, tree diameters at nest positions were lower in this species, compared with other tree species. These results on the ecology of Levaillant’s Woodpecker can serve to fill the information gap in the ornithological knowledge of the Aures forests areas and provide important information for the conservation of the species in the context of forest management practices.
... For secondary cavity nesters, which depend on pre-existing cavities that either form naturally or are previously dug by primary cavity excavators (Newton 1994;Martin and Eadie 1999), cavities are often a limiting resource, and their availability and suitability can drive their population dynamics (Gibbons and Lindenmayer 2002;Aitken and Martin 2008;Banda and Blanco 2009;Lindenmayer et al. 2014;Stojanovic et al. 2016). When introduced into new areas, non-native secondary cavity nesters can only establish where there are available cavities (Pell and Tidemann 1997;Strubbe and Matthysen 2007) or if they can outcompete native species by efficiently exploiting this and other resources through aggressive behaviors (Pell and Tidemann 1997;Koenig 2003;Wiebe 2003, Harper et al. 2005, Strubbe and Matthysen 2009Orchan et al. 2013;Herná ndez-Brito et al. 2014a. Some non-native species may also develop innovative behaviors to increase resource availability in the recipient environment and successfully establish (Sol and Lefebvre 2000;Sol et al. 2002;Wright et al. 2010). ...
Certain traits of recipient environments, such as the availability of limiting resources, strongly determine the establishment success and spread of non-native species. These limitations may be overcome through behavioral plasticity, allowing them to exploit alternative resources. Here, we show how a secondary cavity nester bird, the rose-ringed parakeet Psittacula krameri, innovates its nesting behavior as a response to the shortage of tree cavities for nesting in its invasive range in Tenerife (Canary Islands). We observed that some breeding pairs excavated their own nest cavities in palms, thus becoming primary cavity nester, whereas others occupied nests built with wood sticks by another invasive species, the monk parakeet Myiopsitta monachus. The use of these novel nesting strategies increased the number of breeding pairs by up to 52% over 6 years, contributing to a 128.8% increase of the whole population. Innovative nests were located at greater heights above ground and were more aggregated around conspecifics but did not result in greater breeding success than natural cavities. Occupation of monk parakeet colonies by rose-ringed parakeets also benefited the former species through a protective-nesting association against nest predators. Our results show how an invasive species innovate nesting behaviors and increase nest-site availability in the recipient environment, thus facilitating its population growth and invasion process. Potential behavioral innovations in other invasive rose-ringed parakeet populations may be overlooked, and should be considered for effective management plans.
... The most frequent of the seven bird species detected as secondary-users was the Spotless Starling (59.3% of the occupied woodpecker-excavated cavities), a species known to compete aggressively with other cavity-users for nesting sites (Catry and Catry 2019) similarly to its close relative the European Starling Sturnus vulgaris (Wiebe 2003;Koch et al. 2012). Three other passerine and three non-passerine species benefited from the availability of woodpeckerexcavated cavities (Table 2). ...
Many species of the family Picidae, such as the woodpeckers, excavate the tree-cavities where they nest. Frequently the cavities are used during a single breeding season and subsequently abandoned, which allows their use by non-excavator species for nesting or roosting. Here we analyze the role of woodpeckers as providers of nesting and refuge places in two urban parks in the city of Madrid. The environmental characteristics of the woodpecker nest-sites were also studied. Prior to the breeding season 75 trees bearing woodpecker-excavated cavities and 142 control trees (i.e. without woodpecker cavities) were located, georeferenced and characterized by a set of variables relative to the tree and its environment. During the breeding season the cavities were monitored with an endoscopic camera to verify occupation and user identity. Additionally, 71 non-excavated tree-cavities were monitored to measure their occupancy and make comparisons with those excavated by woodpeckers. Woodpeckers showed a strong preference for trees of the genus Populus: 54 of 75 (72%) woodpecker-cavities were in poplars, which comprised only 7–10% of available trees. The excavated cavities were found mainly in the trunk of the trees, north oriented and away from paths. The occupancy rate by bird species was higher, although not significantly, for excavated cavities than for natural cavities (36.0% and 23.9% respectively). The richness and composition of cavity-user species also differed between types of tree-cavities. This work shows the importance of woodpeckers as providers of nesting and refuge places for other cavity-user birds and highlights their role as ecosystem engineers in urban parks. Finally, we consider that these results can guide biodiversity conservation efforts in urban planning.
... In addition, those events might be mediated by the degree of synchrony in the reproductive phenology of competing species (Samplonius & Both, 2019). Thus, we predicted that interactions will show: (i) an increase over time because, unlike tit populations, the Pied Flycatcher population and its rate of nest box occupation have steadily increased in both areas since the beginning of the study (Camacho et al., 2013); (ii) a higher occurrence when the annual degree of overlap in breeding dates of competing species increases, because greater overlap may entail more competition for nesting sites (Slagsvold, 1975;Källander, 1994;Wiebe, 2003;Ahola et al., 2007;Samplonius et al., 2019); and (iii) a higher occurrence in the pinewood than in the oakwood, since the hole-nesting community of the pinewood is more diverse and nest-site competition should also be stronger due to the scarcity of natural holes there. ...
Pied Flycatchers Ficedula hypoleuca are known to be victims of nest killings in contexts of competition for nest boxes. However, there is only anecdotal information on their opposite role as perpetrators of nest takeovers and occasional killings of other songbirds. Over 31 years we examined whether competition with Great Tits Parus major over nest box ownership is a significant source of mortality for Pied Flycatchers and whether the increase in Pied Flycatcher populations affected the use of nest boxes by the smallest tit species, the Blue Tit Cyanistes caeruleus and Coal Tit Periparus ater, in two forests in the central Iberian Mountain Range. We found 31 Pied Flycatchers killed inside nest boxes. The Great Tit was the most frequent species to which the killings were attributed followed by Pied Flycatchers themselves and Nuthatches Sitta europaea. We confirmed the killing by Pied Flycatchers of at least two conspecific males and one incubating female Coal Tit, with one killer male identified. Large increases in population densities of flycatchers after nest box deployment in the two study areas seem to have triggered an intensification of agonistic interactions among their potential occupants, resulting in an increase of takeovers by Pied Flycatchers of nest boxes initially owned by the smallest tit species. Great Tits are not a serious threat for Pied Flycatchers breeding in the study area, most likely due to their preference for natural holes over the nest box types most frequently installed. The interactions of Pied Flycatchers with Blue and Coal Tits for the ownership of nest boxes do not seem to cause significant mortality in the species involved. However, aggressive usurpations of nest boxes by Pied Flycatchers surely have negative impacts on the reproductive success of the victims through their eviction from suitable nesting sites.
Keywords: competition, contests, hole-nesting, killings, long-term studies, nest usurpations, Paridae.
... The relationship between sturnids and native woodpeckers is similar in other parts of North America where starlings are a deeply entrenched competitor. In British Columbia, competition between starlings and Northern Flickers was found to be high at the beginning of the breeding season and declined rapidly thereafter; for the flickers, delaying reproduction resulted in lower fecundity except when three-quarters or more nests were usurped (Wiebe 2003). Our sample size for Northern Flicker nests (n = 10) was comparatively low, but 40% of nests were usurped by starlings. ...
... Our sample size for Northern Flicker nests (n = 10) was comparatively low, but 40% of nests were usurped by starlings. Flickers in British Columbia had lower rates of active nest usurpations by starlings, ranging from 4.1% to 9.1% (Wiebe 2003). More study is required to determine if starlings represent a serious conservation threat to a woodpecker that is relatively uncommon in our study region. ...
... In tropical Florida, long breeding seasons may allow for delayed reproduction by Red-bellied Woodpeckers without any obvious decline in clutch size or fecundity. The breeding season for cavity-nesting birds was approximately twice as long in Miami, Florida, as in British Columbia (Wiebe 2003). In temperate climates, the delay of reproduction incurs serious fitness costs and reduction of fecundity (Ingold 1996). ...
Multiple invasive cavity-nesting bird species can be present in a nest web, the network linking birds using cavities. We investigated the nest preferences and breeding phenologies of the cavity-nesting guild in the region surrounding Miami, Florida, USA, where invasive starlings, mynas, and parrots potentially usurp cavities from native woodpeckers and secondary cavity-nesters. We asked if the timing of reproduction determines which invasive species will usurp cavities from native birds with similar nest preferences. Nest usurpations between European Starlings (Sturnus vulgaris) and the woodpecker species present in Miami is well documented, but we predicted that a recently arrived sturnid species and introduced psittacids would also usurp nests. European Starlings had the largest breeding population of any species in our nest web, breeding during the peak of nesting season, and usurped the largest number of active nest cavities. We found that a small population of Common Mynas (Acridotheres tristis) usurped nests, sharing the peak-season nesting period with starlings and native woodpeckers. Parrots bred later than we expected, avoiding nest-site overlap with similarly large native birds that use cavities with similar characteristics. Parrots did not usurp any active nest cavities from native birds. Our results demonstrate how to use analysis of cavity characteristics and reproductive timing to evaluate threats to a cavity nest web posed by multiple invasive species. Common Myna currently usurp few nests; if they increase greatly in population, they could pose a problem for native cavity-nesters.
RESUMEN: La superposición de la fenología reproductiva aumenta la probabilidad de usurpación de nidos de cavidad por especies invasoras en una ciudad tropical RESUMEN Muchas especies de aves invasoras que anidan en cavidades pueden estar presentes en una red de nidos, la trama que vincula a las aves que usan cavidades. Investigamos las preferencias de nido y las fenologías reproductivas del gremio de aves que anidan en cavidades en la región que rodea a Miami, Florida, EEUU, donde estorninos, minás y loros invasores potencialmente usurpan las cavidades de carpinteros nativos y de otras aves que anidan secundariamente en cavidades. Nos preguntamos si la fecha de reproducción determina cuáles especies invasores usurparán las cavidades de las especies nativas con preferencias similares de nido. Las usurpaciones de nido de Sturnus vulgaris y las especies de carpinteros presentes en Miami están bien documentadas, pero predijimos que una especie de Sturnidae recientemente llegada y los psitácidos introducidos también podrían usurpar nidos. S. vulgaris tiene la población reproductiva más grande de todas las especies de nuestra red de nidos, anida durante el pico de la estación reproductiva y usurpó el mayor número de cavidades activas. Encontramos que una pequeña población de Acridotheres tristis usurpó nidos, compartiendo el pico de la estación del período de anidación con los estorninos y los carpinteros nativos. Los loros criaron más tarde de lo esperado, evitando la superposición del sitio de anidación con las aves nativas igualmente grandes que usan cavidades con características similares. Los loros no usurparon ningún nido de cavidad activo de las aves nativas. Nuestros resultados demuestran cómo usar el análisis de las características de las cavidades y las fechas de reproducción para evaluar las amenazas a una red de nidos de cavidad que plantean múltiples especies invasoras. A. tristis actualmente usurpa pocos nidos; si aumenta mucho su población, podría plantear un problema a las aves nativas que anidan en cavidades.
... However, prey mismatching is unlikely to be important for flickers, which feed mainly on grounddwelling ants (Gow et al. 2013a(Gow et al. , 2014b) that do not show a sharp seasonal peak (Wiebe and Gow 2013). Accessing such ants does require snow-free ground, however, and the short time window for breeding at this northern locality makes delayed breeding costly (Wiebe 2003). Thus, it is probable that late northward progression of snowmelt during cold springs caused many yearlings to minimize breeding delays by shortening migration distance and settling south of the natal area. ...
Natal dispersal and local recruitment are affected by factors both intrinsic and extrinsic to juveniles and may affect fitness. Understanding the relationship between dispersal and population density in birds has been hindered by a lack of long-term studies and a focus on resident species has neglected the role of weather operating at large spatial scales. I studied local recruitment and the reproductive consequences of natal dispersal distance within a population of Northern Flickers (Colaptes auratus), a migratory woodpecker. During a field study spanning 16 yr in British Columbia, 8,272 fledglings were banded and 138 males and 105 females recruited locally. The average annual local recruitment rate for males (3.36%) was greater than that for females (2.55%) and the propensity to recruit locally was positively correlated with an early hatch date and high body condition. Annual local recruitment was not associated with population density in the year of hatch but was positively correlated with population density in the year of settlement. Local recruitment was also positively correlated with warmer springs during migration, consistent with the phenology hypothesis that the location of settlement is affected by weather along the route. Among local recruits, natal dispersal distance was independent of the presence of parents and so dispersal was not a behavior to prevent inbreeding. However, settling closer to the natal site led to reproductive benefits in terms of earlier laying dates and better nest success. Therefore, juveniles may gain useful information about the location of nesting substrates, predation risk, and patchy food resources by exploring the landscape around their natal site during the post-fledging period and then settling in the familiar area after returning from migration.
... The suitability of these cavities for our study species was based on observed use: we excluded all cavities made by excavators for which our focal species were rarely secondary occupants (<5% use by availability; e.g., Pileated Woodpecker [Dryocopus pileatus]) and, where excavator was unknown or the cavity naturally formed, we excluded cavities that had been initially occupied by secondary nesting species for which our focal species were rarely secondary occupants (<5% use by availability; e.g., northern flying squirrel [Glaucomys sabrinus]). We quantified direct competition between European Starlings and Mountain Bluebirds and Tree Swallows (Koenig 2003, Wiebe 2003, Koch et al. 2012) as the proportion of suitable cavities occupied by nesting starlings in a given year at each of our monitoring sites (Table 1). We also tested whether the abundance of nesting Mountain Bluebirds might delay Tree Swallow nesting given the overlap in cavity preferences between these 2 species and the fact that Mountain Bluebirds initiate earlier than Tree Swallows (Koch et al. 2012, Wiebe 2016. ...
Optimizing breeding phenology, an important aspect of fitness, is complex for migratory species as they must make key timing decisions early, and remotely, from breeding sites. We examined the role of weather (locally and cross-seasonally), cavity availability, and competitive exclusion in determining among-year variation in breeding phenology over 17 yr for 2 migratory, cavity-nesting birds: Mountain Bluebirds (Sialia currucoides; n = 462 nests) and Tree Swallows (Tachycineta bicolor; n = 572) using natural tree cavities in British Columbia, Canada. We assessed weather effects within the winter and migratory range and at our study sites. We quantified competition as the proportion of cavities occupied by European Starlings (Sturnus vulgaris) (for both species) and Mountain Bluebirds (for Tree Swallow only) in each year. For 229 bluebird and 177 swallow nests with known fates, we tested whether late years resulted in reduced productivity. Although the effects were small, heavy rainfall and strong diurnal westerly winds during migration were associated with breeding delays for Mountain Bluebirds. However, cavity availability (earlier breeding with increases) had a 5–8 × greater effect on timing than migratory conditions. There was no evidence that starling competition delayed bluebirds. In Tree Swallows, greater local daily rainfall was associated with delayed breeding, as was starling abundance (the effect of starlings was 1.4 × smaller than that of rainfall). Neither bluebird abundance nor cavity availability changed swallow phenology. Neither species showed reduced productivity in late breeding years. In both species, individuals that bred late relative to conspecifics within-year had smaller clutches and greater probability of nest failure. We conclude that breeding ground conditions, particularly cavity limitation and local rainfall (for swallows), are important drivers of breeding phenology for our focal species, but that the productivity cost of late years, at least for Tree Swallows, is minimal.
