نتایج جستجو برای: third of overwintering birds species 150 species
تعداد نتایج: 21219255 فیلتر نتایج به سال:
the aim of this study is to determine of mercury levels in various internal organs of the fereydunkenar international wetland’s birds for the first time and to determine the influence of this metal on their health. this study has been done in the fereydunkenar international wetland where is the most important wetland habitat of the central areas of hyrcanian ecosystem. fereydunkenar internation...
1. to determine whether difference in birth body mass influenced growth performance in pipistrellus kuhlii we studied a total of 12 captive-born neonates. bats were assigned to two body mass groups: light birth body mass (lbw: 0.89 ± 0.05, n=8) and heavy birth body mass (hbw: 1.35 ± 0.08, n=4). heavier body mass at birth was associated with rapid postnatal growth (body mass and forearm length) ...
126 abstract: in this research we studied the effects of cyclic hydration and dehydration of cysts of artemia urmiana and artemia parthenogenetica on the hatching percentage, survival and growth. the experiment was carried out in 3 treatments (1-3 hydration/dehydration cycles) with 3 replicates for each treatment. later effects of cold preservation at -20°c during three time periods were ...
in this study, a simple, rapid and selective method was developed for the determination of dexamethasone. the proposed method is based on inhibitory effect of dexamethasone on the oxidation of orange-g by bromate in sulfuric acid media. the reaction was followed spectrophotometrically at 478.5 nm (?max). under optimum experimental conditions, (72.6 ?mol l-1 of orange-g, 0.76 mol l-1 of h2so4, 0...
چکیده به منظور بررسی اثر تنوع گیاهی و نوع منبع تغذیه ای بر تنوع و تراکم علفهای هرز و حشرات، کارایی مصرف نهاده ها ( نور، آب، عناصر غذایی) و عملکرد و خصوصیات کیفی چند گونه زراعی، آزمایشی به صورت کرتهای خردشده بر پایه طرح بلوکهای کامل تصادفی با سه تکرار در دو سال زراعی 1385-1384 و 1386-1385 در مزرعه تحقیقاتی دانشکده کشاورزی دانشگاه فردوسی مشهد به اجرا درآمد. تیمارهای مورد بررسی دو منبع کود دامی و...
Nearly one in five bird species has separate breeding and overwintering distributions, and the regular migrations of these species cause a substantial seasonal redistribution of avian diversity across the world. However, despite its ecological importance, bird migration has been largely ignored in studies of global avian biodiversity, with few studies having addressed it from a macroecological ...
In this study, the trend of overwintering and breeding populations of the endangered white-headed duck Oxyura leucocephala was studied using 52 years of mid-winter waterbirds census in Iran (1969–2020) and breeding reports of the species in the 2010s. The trend of species population changes was calculated using RTRIM statistical package in R software. Species population in Iran indicates a subs...
background: corvidae is a cosmopolitan family of oscine birds including crows, rooks, magpies, jays, chough, and ravens. these birds are migratory species, especially in the shortage of foods, so they can act like vectors for a wide range of microorganisms. they live generally in temperate climates and in a very close contact with human residential areas as well as poultry farms. there is no ...
Migratory connectivity by birds may mutually affect different ecosystems over large distances. Populations of geese overwintering in southern areas while breeding in high-latitude ecosystems have increased strongly over the past decades. The increase is likely due to positive feedbacks caused by climate change at both wintering, stopover sites and breeding grounds, land-use practices at the ove...
b ackground: although there are about 520 species of birds in iran, but only some of them have been checked for ectoparasites so far.the aim of this study was to check some more available species of the birds of iran for lice. m ethods: this study was performed between 2008–2010 in northern iran. for this purpose we tried to check some of the wild bird species available and mostly not checked b...
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