scholarly journals Nesting biology of the Hooded Crow Corvus corone cornix in a mixed residential–agricultural area in southern Sweden

Ornis Svecica ◽  
2010 ◽  
Vol 20 (2) ◽  
Author(s):  
Rebecca Hessel ◽  
Johan Elmberg
Keyword(s):  
Hatching Success ◽  
Canopy Cover ◽  
Forest Edge ◽  
Southern Sweden ◽  
Land Area ◽  
Nesting Biology ◽  
Significant Bias ◽  
Corvus Corone ◽  
Pine Trees ◽  
Hooded Crows

We studied 11 active and 29 old nests of Hooded Crows Corvus corone cornix in a mixed residential-farmland landscape (3.6 km2) in southern Sweden in 2009. The density of active nests was 3.06/km2 land area and 7.33/km2 forest area. Thirty-eight nests were in pine-dominated forest and two in private gardens. All nests (active and old) were in pine trees Pinus sylvestris, and sample plots around nest trees had the following characteristics (means): 350 tree stems/hectare, 1,487 bushes/ hectare, and canopy cover 8%. Distance to the nearest active Crow nest averaged 234 m, but variation was large. Mean distance from nests to nearest forest edge was 19 m and to the nearest inhabited building 68 m. Nests were placed near the tree top (mean height 11 m) in all cardinal directions but with a significant bias towards the south. Seven out of 11 (64%) active nests produced fledglings (mean 1.2 nestling/successful nest). Breeding success was higher in nests that were close to another crow nest. Compared with previous studies, hatching success was high but final fledgling production was low.

PERÍODO DE DESOVA E SUCESSO REPRODUTIVO DO TRACAJÁ Podocnemis unifilis TROSCHEL 1848 (TESTUDINES: PODOCNEMIDIDAE) NA VÁRZEA DA RDSM – MÉDIO SOLIMÕES, BRASIL

2008 ◽  
Vol 2 (1) ◽  
pp. 63-75
Author(s):  
Augusto Fachín Terán ◽  
Eduardo Matheus Von Mülhen
Keyword(s):  
Hatching Success ◽  
Management Program ◽  
Nesting Biology ◽  
Sand Beach ◽  
Podocnemis Unifilis ◽  
Turtle Population ◽  
Nesting Beaches ◽  
Conservation And Management ◽  
Tegu Lizard ◽  
Solimões River

In this study the nesting biology of Podocnem is unifilis was investigated from July to November 1998 at the Mamirauá Sustainable Development Reserve, located in the Solimões river, near Tefé, Amazonas, Brazil. Podocnemis unifilis nested in August and September, with the hatching event occurring in October and November. Nests were excavated in clay soils (67.5%), sand (25%), and leaf litter (7.5%). Hatching success was highest in the sand beach nests and lowest in the clay banks nests. Humans and the tegu lizard (Tupinambis) were the main egg predators. This turtle population can recover only by the protection of nesting beaches, educational programs for the in habitants of the Reserve, participation of the community in the conservation and management program , and permanent guarding of the nesting beaches by Instituto Brasileiro do Meio Ambiente e Dos Recursos Naturais Renováveis-IBAMA authorities.

scholarly journals Estimating vertical canopy cover using dense image-based point cloud data in four vegetation types in southern Sweden

2017 ◽  
Vol 38 (7) ◽  
pp. 1820-1838 ◽  
Author(s):  
Ann-Helen Granholm ◽  
Nils Lindgren ◽  
Kenneth Olofsson ◽  
Mattias Nyström ◽  
Anna Allard ◽  
...  
Keyword(s):  
Point Cloud ◽  
Canopy Cover ◽  
Point Cloud Data ◽  
Vegetation Types ◽  
Southern Sweden ◽  
Cloud Data ◽  
Dense Image

Aggressive behaviour in Montagu’s harrier Circus pygargus during the courtship period

Biologia ◽  
2006 ◽  
Vol 61 (5) ◽  
Author(s):  
Jarosław Wiącek
Keyword(s):  
Aggressive Behaviour ◽  
Aggressive Interactions ◽  
Circus Pygargus ◽  
Circus Aeruginosus ◽  
Corvus Corone ◽  
Montagu’S Harrier ◽  
Asio Flammeus ◽  
Hooded Crows ◽  
First Time ◽  
Montagu's Harrier

AbstractAggressive behaviour of Montagu’s harrier was observed during the pre-laying period in the 1992–1995 seasons on the calcareous marshes of Chelm in Eastern Poland. In total, 435 flights performed by 24 pairs of individually marked harriers were analysed. All flights were performed in relation to the territory of defence. Males performed 61% of aggressive interactions while females performed 39%. Intraspecific and interspecific aggression comprising direct attacks (58%), escorts (13%), pursuits (28%) and “mirror behaviour” (1%) were described for the first time. Interspecific aggressive behaviour occurred only near territory boundaries. The main intruders were marsh harriers Circus aeruginosus breeding on the same marshes. Occasionally, harriers attacked curlews Numenius arquata, short-eared owls Asio flammeus, magpies Pica pica, hooded crows Corvus corone cornix, common buzzards Buteo buteo or hobbies Falco subbuteo. Four cases of communal mobbing were observed. Three to five males from the neighbourhood attacked the intruders together. Intraspecific aggressive behaviour was observed in the pair territory, near the boundary or at a distance of up to 100 m from the defended area. Aggressive interactions performed by both sexes were more frequent towards birds of the same sex. Females defended their territories more aggressively against females. Similarly, males were more aggressive against males. All cases of aggressive behaviour were observed near harrier territories. Aggressive relations between birds outside breeding territories or when foraging around marshes were not observed.

scholarly journals Estimation of crown and canopy cover from airborne lidar data

2010 ◽  
Vol 52 (1) ◽  
pp. 5-17 ◽  
Author(s):  
Mait Lang
Keyword(s):  
Norway Spruce ◽  
Scots Pine ◽  
Stand Structure ◽  
Canopy Cover ◽  
Airborne Lidar ◽  
Silver Birch ◽  
Lidar Data ◽  
Crown Cover ◽  
Pine Trees ◽  
Airborne Lidar Data

Metsa katvuse ja liituse hindamine lennukilt laserskanneriga Tests were carried out in mature Scots pine, Norway spruce and Silver birch stands at Järvselja, Estonia, to estimate canopy cover (K) and crown cover (L) from airborne lidar data. Independent estimates Kc and Lc for K and L were calculated from the Cajanus tube readings made on the ground at 1.3 m height. Lidar data based cover estimates depended on the inclusion of different order returns significantly. In all the stands first order return based estimate K1 was biased positively (3-10%) at the reference height of 1.3 m compared to ground measurements. All lidar based estimates decreased with increasing the reference height. Single return (Ky) and all return (Kk) based canopy cover estimates depended more on the sand structure compared to K1. The ratio of all return count to the first return count D behaved like crown cover estimate in all stands. However, in spruce stand D understimated Lc significantly. In the Scots pine stand K1(1.3) = 0.7431 was most similar canopy cover estimate relative to the ground estimate Kc = 0,7362 whereas Ky(1.3) and Kk(1.3) gave significant underestimates (>15%) of K. Caused by the simple structure of Scots pine stand - only one layer pine trees, the Cajanus tube based canopy cover (Kc), crown cover (Lc) and lidar data based canopy density D(1.3) values were rather similar. In the Norway spruce stand and in the Silver birch stand second layer and regeneration trees were present. In the Silver birch stand Kk(1.3) and Ky(1.3) estimated Kc rather well. In the Norway spruce stand Ky(1.3) and K1(1.3) were the best estimators of Kc whereas Kk(1.3) underestimated canopy cover. Lidar data were found to be usable for canopy cover and crown cover assessment but the selection of the estimator is not trivial and depends on the stand structure.

Food Caching, Cache Recovery, and the Use of an Egg Shell Dump in Hooded Crows Corvus corone cornix

1988 ◽  
Vol 19 (4) ◽  
pp. 268 ◽  
Author(s):  
Per E. Fjeld ◽  
Geir A. Sonerud
Keyword(s):  
Food Caching ◽  
Corvus Corone ◽  
Cache Recovery ◽  
Egg Shell ◽  
Hooded Crows

scholarly journals Edge effect on carabid assemblages along forest-grass transects

Web Ecology ◽  
2001 ◽  
Vol 2 (1) ◽  
pp. 7-13 ◽  
Author(s):  
T. Magura ◽  
B. Tóthmérész ◽  
T. Molnár
Keyword(s):  
Edge Effect ◽  
Abiotic Factors ◽  
Canopy Cover ◽  
Distinct Species ◽  
Forest Edge ◽  
Principal Coordinates Analysis ◽  
Forest Interior ◽  
Principal Coordinates ◽  
Significant Edge ◽  
Characteristic Species

Abstract. During 1997 and 1998, we have tested the edge-effect for carabids along oak-hornbeam forest-grass transects using pitfall traps in Hungary. Our hypothesis was that the diversity of carabids will be higher in the forest edge than in the forest interior. We also focused on the characteristic species of the habitats along the transects and the relationships between their distribution and the biotic and abiotic factors. Our results proved that there was a significant edge effect on the studied carabid communities: the Shannon diversity increased significantly along the transects from the forest towards the grass. The diversity of the carabids were significantly higher in the forest edge and in the grass than in the forest interior. The carabids of the forest, the forest edge and the grass are separated from each other by principal coordinates analysis and by indicator species analysis (IndVal), suggesting that each of the three habitats has a distinct species assemblages. There were 5 distinctive groups of carabids: 1) habitat generalists, 2) forest generalists, 3) species of the open area, 4) forest edge species, and 5) forest specialists. It was demonstrated by multiple regression analyses, that the relative air moisture, temperature of the ground, the cover of leaf litter, herbs, shrubs and canopy cover, abundance of the carabids’ preys are the most important factors determining the diversity and spatial pattern of carabids along the studied transects.

scholarly journals Evaluating the Capability of Unmanned Aerial System (UAS) Imagery to Detect and Measure the Effects of Edge Influence on Forest Canopy Cover in New England

Forests ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1252
Author(s):  
Heather Grybas ◽  
Russell G. Congalton
Keyword(s):  
New England ◽  
Forest Canopy ◽  
Canopy Cover ◽  
Point Clouds ◽  
Forest Edge ◽  
P Value ◽  
Unmanned Aerial Systems ◽  
Forest Edges ◽  
Significant Edge ◽  
The Face

Characterizing and measuring the extent of change at forest edges is important for making management decisions, especially in the face of climate change, but is difficult due to the large number of factors that can modify the response. Unmanned aerial systems (UAS) imagery may serve as a tool to detect and measure the forest response at the edge quickly and repeatedly, thus allowing a larger amount of area to be covered with less work. This study is a preliminary attempt to utilize UAS imagery to detect changes in canopy cover, known to exhibit changes due to edge influences, across forest edges in a New England forest. Changes in canopy cover with increasing distance from the forest edge were measured on the ground using digital cover photography and from photogrammetric point clouds and imagery-based maps of canopy gaps produced with UAS imagery. The imagery-based canopy gap products were significantly more similar to ground estimates for canopy cover (p value > 0.05) than the photogrammetric point clouds, but still suffered overestimation (RMSE of 0.088) due to the inability to detect small canopy openings. Both the ground and UAS data were able to detect a decrease in canopy cover to between 45–50 m from the edge, followed by an increase to 100 m. The UAS data had the advantage of a greater sampling intensity and was thus better able to detect a significant edge effect of minimal magnitude effect in the presence of heavy variability.

Geographic variation in size and sexual dimorphism across a hybrid zone between Carrion Crows (Corvus corone corone) and Hooded Crows (C. c. cornix)

1994 ◽  
Vol 72 (9) ◽  
pp. 1543-1550 ◽  
Author(s):  
Nicola Saino ◽  
Fiorenza De Bernardi
Keyword(s):  
Hybrid Zone ◽  
Sexual Size Dimorphism ◽  
Function Analysis ◽  
Absolute Difference ◽  
Ecological Gradient ◽  
Size Dimorphism ◽  
Operational Taxonomic Units ◽  
Corvus Corone ◽  
Males And Females ◽  
Hooded Crows

Sexual size dimorphism was analysed across a hybrid zone existing between allopatric populations of Carrion Crows and Hooded Crows (Corvus corone corone and C. c. cornix) in northwestern Italy. Twenty-five morphological (osteological and plumage) variables were measured in a sample of 1599 specimens obtained from allopatric parental areas and from the hybrid zone. For each morphological variable considered, sexual size dimorphism was measured as the ratio of males/females or the absolute difference between mean sizes of males and females within each subpopulation studied. Overall sexual size dimorphism was described by discriminant function analysis. All the sexual size dimorphism measures adopted showed variation across the hybrid zone according to elevation. Male/female ratios and male–female differences significantly differed between the parental allopatric "operational taxonomic units," Carrion Crows being more dimorphic than Hooded Crows. Across the hybrid zone, sexual size dimorphism was correlated with the phenotypic composition of the crow subpopulations and with size of males but not size of females. The data presented show that sexual size dimorphism is correlated with an ecological gradient and that its geographical variation is determined by variation in size of males only.

Dermatophilus spp. and Candida spp. Infections In Free-Living Hooded Crows (Corvus corone cornix)

2016 ◽  
Vol 154 (1) ◽  
pp. 119 ◽  
Author(s):  
F.E. Scaglione ◽  
L. Starvaggi Cucuzza ◽  
P. Pregel ◽  
L. Chiappino ◽  
A. Sereno ◽  
...  
Keyword(s):  
Candida Spp ◽  
Free Living ◽  
Corvus Corone ◽  
Hooded Crows
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