Seasonal Differences in Immunological Condition of Three Species of Thrushes

Abstract Migratory birds are exposed to a diverse pathogen fauna by virtue of their long-distance travels. Although the immune system is an organism's primary defense against pathogenic microorganisms, few studies have investigated avian immune function during migration, much less shown seasonal differences in immune function. We describe the immunological condition of three intercontinental migratory species, Swainson's Thrush (Catharus ustulatus), Veery (C. fuscescens), and Wood Thrush (Hylocichla mustelina) during spring migration. In addition, we compare their immunological condition with conspecifics captured during fall migration and during the breeding season to provide a frame of reference for the spring immunological data. Measures of immunological condition presented include total leukocyte count, heterophil:lymphocyte (H:L) ratio, heterophil and lymphocyte counts, hematocrit, and IgG titers. In addition, we assessed each bird's energetic condition by measuring body mass and calculating a size-corrected condition index. Migrating birds had lower leukocyte and lymphocyte counts, lower hematocrit, reduced fat stores, and higher H:L ratios relative to nonmigrating individuals sampled during the breeding season. We also found that birds sampled during spring migration had lower lymphocyte counts and reduced fat stores, and higher heterophil counts and H:L ratios than fall migrants. Our results suggest that migrating birds are immunocompromised compared with conspecifics during the breeding season. Furthermore, compared with conspecifics sampled after a shorter overland flight, migrants sampled after crossing the Gulf of Mexico exhibited higher H:L ratios, which is indicative of heightened energetic stress.

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Migrating birds rapidly increase constitutive immune function during stopover

Royal Society Open Science ◽

10.1098/rsos.192031 ◽

2020 ◽

Vol 7 (2) ◽

pp. 192031 ◽

Cited By ~ 2

Author(s):

Cas Eikenaar ◽

Sven Hessler ◽

Arne Hegemann

Keyword(s):

Immune Function ◽

Migratory Bird ◽

Long Distance ◽

Stopover Site ◽

Multiple Parameters ◽

Migratory Flight ◽

Stopover Sites ◽

Food Conditions ◽

Fuel Accumulation ◽

Migrating Birds

Migratory flight is physiologically highly demanding and has been shown to negatively affect multiple parameters of constitutive immune function (CIF), an animal's first line of physiological defence against infections. In between migratory flights, most birds make stopovers, periods during which they accumulate fuel for the next flight(s). Stopovers are also commonly thought of as periods of rest and recovery, but what this encompasses is largely undefined. Here, we show that during stopover, northern wheatears Oenanthe oenanthe, a long-distance migratory bird, can rapidly increase constitutive innate immune function. We caught and temporarily caged birds under ad libitum food conditions at a stopover site in autumn. Within 2 days, most birds significantly increased complement activity and their ability to kill microbes. Changes in immune function were not related to the birds' food intake or extent of fuel accumulation. Our study suggests that stopovers may not only be important to refuel but also to restore immune function. Additionally, the increase in CIF could help migrating birds to deal with novel pathogens they may encounter at stopover sites.

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Reversal of the adipostat control of torpor during migration in hummingbirds

10.1101/2021.05.13.443997 ◽

2021 ◽

Author(s):

Erich R Eberts ◽

Chris Guglielmo ◽

Kenneth C Welch

Keyword(s):

Body Composition ◽

Energy Balance ◽

Magnetic Resonance ◽

Late Summer ◽

Fundamental Change ◽

Long Distance ◽

Daily Energy ◽

Physiological Feedback ◽

Fat Stores ◽

Migrating Birds

Many small endotherms use torpor to reduce metabolic rate and manage daily energy balance. However, the physiological 'rules' that govern torpor use are unclear. We tracked torpor use and body composition in ruby-throated hummingbirds (Archilochus colubris), a long-distance migrant, throughout the summer using respirometry and quantitative magnetic resonance. During the mid-summer, birds entered torpor at consistently low fat stores (~5% of body mass), and torpor duration was negatively related to evening fat load. Remarkably, this energy-emergency strategy was abandoned in the late summer when birds accumulated fat for migration. Migrating birds were more likely to enter torpor on nights when they had higher fat stores, and fat gain was positively correlated with the amount of torpor used. These findings demonstrate the versatility of torpor throughout the annual cycle and suggest a fundamental change in physiological feedback between adiposity and torpor during migration. Moreover, this study highlights the underappreciated importance of facultative heterothermy in migratory ecology.

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Seasonal differences in migration strategies of Red Kites (Milvus milvus) wintering in Spain

Journal of Ornithology ◽

10.1007/s10336-021-01918-5 ◽

2021 ◽

Author(s):

Jorge García-Macía ◽

Javier Vidal-Mateo ◽

Javier De La Puente ◽

Ana Bermejo ◽

Rainer Raab ◽

...

Keyword(s):

Spring Migration ◽

Great Variability ◽

Autumn Migration ◽

Seasonal Differences ◽

North Eastern ◽

Wintering Areas ◽

Satellite Transmitters ◽

Migration Strategies ◽

Migratory Movements ◽

Milvus Milvus

AbstractRed Kite shows a great variability in its migration strategies: most individuals in north-eastern Europe are migrants, but there is also a growing number of sedentary individuals. Here, we tagged 49 Red Kites wintering in Spain with GPS/satellite transmitters between 2013 and 2020 to study the autumn and spring migration between the breeding or summering areas in Central Europe and the wintering quarters in Spain. In first place, differences between immatures and adults were found for spring migration. Adults began the spring migration towards the northeast in February–March while the immature individuals began to migrate significantly later and showing a wider date range (February-June). Adults also takes significantly less days to arrive at their destinations (12 ± 5 days) and cover more distance per day (134.2 ± 37.1 km/day) than immatures (19 ± 11 days and 98.9 ± 21.2 km/day). In second place, we also found differences between spring and autumn migration (excluding immatures). Spring migrations were clearly faster and with less stopovers days than autumn migrations. Autumn migration began between mid-October and late November and two different behaviours were observed: most birds made a quick migration direct to the wintering areas with only some days of stopovers, but others prolonged the migration with long stops along the route. These results highlight a great variation in the migratory movements of Red Kite, not only according to age but also between individuals and seasons.

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Limited Access to Food and Physiological Trade‐Offs in a Long‐Distance Migrant Shorebird. II. Constitutive Immune Function and the Acute‐Phase Response

Physiological and Biochemical Zoology ◽

10.1086/603635 ◽

2009 ◽

Vol 82 (5) ◽

pp. 561-571 ◽

Cited By ~ 41

Author(s):

Deborah M. Buehler ◽

Francisco Encinas‐Viso ◽

Magali Petit ◽

François Vézina ◽

B. Irene Tieleman ◽

...

Keyword(s):

Immune Function ◽

Acute Phase ◽

Acute Phase Response ◽

Phase Response ◽

Long Distance ◽

Limited Access ◽

Trade Offs ◽

Access To Food

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PSVII-5 Effect of yeast, astragalus polysaccharide or tulathromycin administration on immune function of transported heifers

Journal of Animal Science ◽

10.1093/jas/skaa278.543 ◽

2020 ◽

Vol 98 (Supplement_4) ◽

pp. 303-304

Author(s):

Xin Wu ◽

Qingxiang Meng ◽

Hao Wu ◽

Paul A Beck

Keyword(s):

Immune Function ◽

Repeated Measures ◽

Basal Diet ◽

Blood Parameters ◽

Long Distance ◽

Performance Loss ◽

Long Distance Transport ◽

Medication Costs ◽

Astragalus Polysaccharide ◽

Distance Transport

Abstract Transportation stress of beef calves results in decreased performance and increased medication costs. The hypothesis of the current research was that yeast, astragalus polysaccharide, or tulathromycin administration would enhance immune function and alleviate the performance loss caused by long-distance transport. Angus heifers (n = 80) were ranked by BW on d -7 and assigned to 1 of 4 treatments before shipping 1,400 km: 1) fed a basal diet (CON) 2) administered yeast product (20 g/heifer daily) in basal diet from d -7 to 7 (YEA); 3) administration of astragalus polysaccharide (20 g/heifer daily) in basal diet from d -7 to 7 (APS); or 4) administration of tulathromycin (0.025 mL/kg BW subcutaneous injection) at loading (d 0; TUL). During transport (29 h duration) cattle remained in the trucks at all times. Upon arrival (d 1), heifers within each treatment were ranked by BW and assigned to 20 feedlot pens (5 pens/treatment, 4 heifers/pen). Blood was collected on d -7, -1, 1, and 7. Blood parameters among treatments over time were compared by SAS using linear mixed models with repeated measures. Over the receiving period, ADG were less (P < 0.01) for CON than YEA, APS and TUL but did not differ among these groups. A treatment × day interaction was detected for neutrophil, IgA and IgG (P < 0.05), where neutrophil was lower in YEA and APS than in TUL and CON on d 1 (P < 0.05). Serum IgA was higher in YEA and APS than in CON and TUL on d 1 (P < 0.05), serum IgG was higher in APS than in YEA, CON and TUL on d 1 and 7 (P < 0.05). In conclusion, APS and YEA could enhance immune function, resulting in alleviating the performance loss caused by long-distance transport.

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The breeding season and diet of Arvicanthis in northern Nigeria

Journal of Tropical Ecology ◽

10.1017/s0266467400003837 ◽

1989 ◽

Vol 5 (4) ◽

pp. 375-386 ◽

Cited By ~ 9

Author(s):

Safianu Rabiu ◽

Martin Fisher

Keyword(s):

Breeding Season ◽

Food Supply ◽

Rainy Season ◽

Dry Season ◽

Northern Nigeria ◽

East African ◽

African Savanna ◽

Seasonal Differences ◽

Sudan Savanna ◽

Semi Arid

ABSTRACTThe breeding season and diet of the rat Arvicanthis was monitored from December 1983 to November 1985 in the semi-arid Sudan savanna at Kano, Nigeria, West Africa. Breeding began 1–2 months before the start of the rainy season and ceased at the beginning of the dry season. The diet of Arvicanthis was omnivorous, but with seasonal differences. Monocotyledons and dicotyledons predominated in the diet in the dry season, with seeds and insects increasing in the diet in the rainy season. The major differences between the ecology of Arvicanthis at Kano and on the East African savanna were that in East Africa the breeding season is longer and begins after the start of the rainy season. These and other dissimilarities between the biology of Arvicanthis in the two areas could be due to the effect of climatic differences on food supply and to the possible existence of different taxonomic groupings of Arvicanthis in the two regions.

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Are we underestimating the threat to Australia’s migratory land birds?

Pacific Conservation Biology ◽

10.1071/pc130303 ◽

2013 ◽

Vol 19 (4) ◽

pp. 303 ◽

Cited By ~ 2

Author(s):

Hugh A Ford

Keyword(s):

North America ◽

Breeding Season ◽

Northern Australia ◽

The South ◽

Long Distance ◽

Wintering Grounds ◽

Limited Knowledge ◽

Wintering Areas ◽

Near Future ◽

Near Threatened

Few migratory land birds in Australia are currently regarded as threatened or near threatened. In contrast, many of Australia’s migratory seabirds and shorebirds are threatened or near threatened, with most of the latter being added over the last two decades. Furthermore, many long-distance migratory land birds that breed in North America and Europe have experienced major declines, probably due to threats in their breeding or wintering grounds or both. I suggest that knowledge of our migratory land birds is limited, and almost non-existent outside their breeding areas. Some are already declining and I predict that others will decline in the near future. The priority now is to increase our knowledge of the locations of major wintering areas in northern Australia of land birds that breed in the south, and to study their ecology and behaviour outside the breeding season. We also have limited knowledge of how migrants in Australia prepare physiologically and behaviourally for migration. If they migrate in large hops, then we need to find and protect departure, refuelling and arrival sites.

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Ontogeny of Large Birds: Migrants do it Faster

The Condor ◽

10.1093/condor/106.3.540 ◽

2004 ◽

Vol 106 (3) ◽

pp. 540-548 ◽

Cited By ~ 1

Author(s):

Shai Meiri ◽

Yoram Yom-Tov

Keyword(s):

Incubation Period ◽

Developmental Period ◽

Long Distance ◽

Weak Evidence ◽

Migrating Birds

Abstract We compared incubation and fledging times between large (>2 kg) migrating and sedentary birds. We found that while length of incubation period does not differ between migrants and nonmigrants, fledging period is significantly shorter in the former. This pattern is apparent in the class as a whole, as well as within orders, families, and genera. Additional, albeit weak, evidence suggests that clutch sizes of migrants are smaller than those of closely related resident birds. We hypothesize that the need to migrate constrains the length of developmental period of large migrating birds, especially in species that undertake long-distance migration. Ontogenia de Aves Grandes: Los Migrantes lo Hacen más Rápido Resumen. Comparamos los tiempos de incubación y emplumamiento entre aves grandes (>2 kg) migratorias y sedentarias. Encontramos que mientras la longitud del período de incubación no difiere entre migrantes y no migrantes, el período de emplumamiento es significativamente más corto en las migrantes. Este patrón resulta evidente a nivel de toda la clase, así como al interior de órdenes, familias y géneros. Existe evidencia adicional, aunque débil, que sugiere que las nidadas de las migrantes son más pequeñas que las de aves residentes estrechamente relacionadas. Proponemos la hipótesis de que la necesidad de migrar limita la longitud del período de desarrollo de las aves migrantes grandes, especialmente en las especies que realizan migraciones a través de grandes distancias.

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Perinatal photoperiod organizes adult immune responses in Siberian hamsters (Phodopus sungorus)

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00869.2005 ◽

2006 ◽

Vol 290 (6) ◽

pp. R1714-R1719 ◽

Cited By ~ 28

Author(s):

Zachary M. Weil ◽

Leah M. Pyter ◽

Lynn B. Martin ◽

Randy J. Nelson

Keyword(s):

Immune System ◽

Immune Function ◽

Breeding Season ◽

Somatic Growth ◽

Developmental Trajectory ◽

Day Length ◽

Phodopus Sungorus ◽

Siberian Hamsters ◽

Time Of Year ◽

Induced Changes

Individuals of many nontropical rodent species display reproductive, immunological, and somatic responses to day length. In general, short day (SD) lengths inhibit reproduction and enhance immune function in the laboratory when all other conditions are held constant. Most studies to date have focused on seasonal variation in immune function in adulthood. However, perinatal photoperiods also communicate critical day length information and serve to establish a developmental trajectory appropriate for the time of year. Nontropical rodents born early in the breeding season undergo rapid reproductive development, presumably to promote mating success during their first reproductive season. Rodents born late in the breeding season suspend somatic growth and puberty until the following vernal breeding season. We tested the hypothesis that perinatal day lengths have similar enduring effects on the immune system of rodents. Siberian hamsters ( Phodopus sungorus) were maintained prenatally and until weaning (21 days) in either SDs (8 h light:16 h dark) or long days (LD) (16 h light:8 h dark), then they were weaned into either the opposite photoperiod or maintained in their natal photoperiod, forming four groups (LD-LD, LD-SD, SD-LD, and SD-SD). After 8-wk in these conditions, cell-mediated immune activity was compared among groups. SD-SD hamsters of both sexes enhanced immune function relative to all other groups. The reproductive effects of perinatal photoperiod were not evident by the end of the experiment; circulating testosterone and cortisol sampled at the end of the experiment reflected the postweaning, but not the perinatal photoperiod. This experiment demonstrates long-lasting organizational effects of perinatal photoperiod on the rodent immune system and indicates that photoperiod-induced changes in the immune system are dissociable from changes in the reproductive system.

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Relationship between energetic condition and indicators of immune function in thrushes during spring migration

Canadian Journal of Zoology ◽

10.1139/z08-038 ◽

2008 ◽

Vol 86 (7) ◽

pp. 638-647 ◽

Cited By ~ 36

Author(s):

J. C. Owen ◽

F. R. Moore

Keyword(s):

Immune Response ◽

Immune Function ◽

Spring Migration ◽

Hylocichla Mustelina ◽

Catharus Ustulatus ◽

Stopover Site ◽

Lymphocyte Ratio ◽

Energetic Condition ◽

In Captivity ◽

Immunoglobulin Gamma

Evidence suggests that the ability of an animal to maintain its immune system and (or) mount an immune response depends on its nutritional health and energetic condition. Migration is a period within an animal’s annual cycle when energetic condition varies, especially after a long, nonstop flight over a large ecological barrier. Our objective was to determine if measures of immune function in migrating Wood Thrush ( Hylocichla mustelina (J.F. Gmelin, 1789)), Swainson’s Thrush ( Catharus ustulatus (Nuttall, 1840)), Gray-cheeked Thrush ( Catharus minimus (Lafresnaye, 1848)), and Veery ( Catharus fuscescens (Stephens, 1817)) were related to the energetic condition of the birds at a stopover site during spring migration. We present data on total leukocyte, lymphocyte, and heterophil counts, heterophil/lymphocyte ratio, serum immunoglobulin gamma G (IgG) concentration, and immune response to phytohemagglutinin. Thrushes arriving at the stopover site in poor energetic condition had low leukocyte and lymphocyte counts. Heterophil/lymphocyte ratio, heterophil count, and IgG concentration were not related to energetic condition. Furthermore, immune response to phytohemagglutinin was positively related to change in mass and days spent in captivity, suggesting that immune function may improve during stopover. We suggest that migrating thrushes arriving at a stopover site in poor energetic condition may also be in poor immunological condition and may have increased susceptibility to disease or parasite infection.

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