R E P O R T S

I LLINOIS NATURAL HISTORY S U RVE Y R e p o r t s

May/ June 1998 No. 351 I N S I D E Don't Blame It All on the Raccoons

Much of the natural habitat of nesting song- Long-term Dormancy the midwestern U.S. has been birds do not in Freshwater converted to agricultural use. In fl edge enough Zooplankton east-central Illinois, for example, young to main- 2 row-crop agriculture covers tain stable pop- about 75% of the land area and ulations. These dominates the landscape. The areas may be Wetland Bird Conser- remaining natural areas are also population vation in Northeastern typically highly fragmented, sinks for song- Illinois creating large amounts of edge birds, meaning 3 habitat. Recent conservation that popula- literature has focused primarily tions must be Illinois Earthworms: In- on the negative aspects of such maintained by dicators of Soil Health? habitat fragmentation, but some constant immi- 4 species thrive in these heteroge- gration. Many neous areas. In fact, medium- kinds of preda- sized mammalian predators, such tors take song- Species Spotlight: as coyotes, raccoons, and opos- bird nests, but at ce of the Chief INHS Offi Photo by Steve Bailey, Passenger Pigeon sums, have increased to what are least two studies 6 probably historic high densities in the Midwest in Illinois in the past few decades have implicated despite extensive conversion of the raccoon as The Naturalist's natural habitats to agriculture. the major preda- Apprentice: These species tend to be very tor in agricul- Passenger Pigeon opportunistic in their choice of tural regions. A fox snake, one of several predators of songbirds. Colors food and habitat, as long as cer- So far, though, 7 tain basic requirements, such as few data show suitable den sites, are met. Some how different types of predators use recent studies have shown that habitat edges. raccoons reach their highest num- At the Middle Fork Fish and Resources, being conducted by ...two studies bers in landscapes with extensive Wildlife Area in Vermilion County, Scott Robinson, Jeff Brawn, Ed agricultural edges, in wooded we radio tracked 15 raccoons and Heske, and other INHS biologists in the Midwest remnants in areas with extensive 4 opossums to determine whether to study factors affecting nest corn cover, and in fragmented they used habitat edges preferen- predation on edge-, shrubland-, have impli- landscapes with a high diversity tially. We also conducted experi- and grassland-nesting songbirds. of cover types, especially where ments using wicker nests baited We tracked radio-collared cated the rac- there is proximity to water. with commercial quail and Zebra raccoons and opossums at night The good news for some kinds Finch eggs to determine if rates from two vehicles with antennae coon as the of animals can be bad news for of predation differed in fi elds of mounted on the roofs. Coordinat- major predator others, though. Predators may different sizes (are predation rates ing our positions and timing by use habitat edges as travel lanes lower in large fi elds?) or at differ- CB radio, we recorded simulta- in agricultural or forage more intensely there, ent distances from habitat edges neous bearings for each animal elevating rates of predation on (are predation rates higher closer to several times per night between regions. songbird nests. In some areas the edge than out in the middle of about 9 p.m. and 4 a.m. during of the Midwest where habitat the fi eld?). This research is part of three-week tracking sessions in fragmentation is extensive, rates a Federal Aid in Fish and Wildlife June and August 1997. Using of predation and nest parasitism Restoration project, funded through a differential global positioning by cowbirds can be so high that the Illinois Department of Natural Continued on back page

1 Long-term Dormancy in Freshwater Zooplankton

Zooplankton (microscopic organ- pausing eggs can accumulate in isms suspended in water) are an densities ranging from 1,000 to 1 important component of a diverse million eggs per m2 of sediment. array of aquatic systems. Al- This storage of dormant stages though zooplankton differ in form forms an “egg bank” that is in and function, one trait common to many ways analogous to the seed a variety of species is the ability to banks of various terrestrial plant produce two types of eggs. Dur- species. One consequence of

ing favorable conditions, females storing dormant stages in either Aquatic Ecology produce subitaneous eggs, which a terrestrial or aquatic system is develop immediately. When en- that it creates a reservoir of both

vironmental conditions begin to species and genetic diversity. Photo by Carla Cáceres, INHS Center for decline for any number of reasons, This storage of biodiversity will females can switch to producing affect the way in which a system diapausing (resting) eggs, which responds to both natural and arti- Adult Daphnia pulicaria with enter a period of dormancy before ﬁ cial changes. diapausing eggs. In Daphnia the resuming development. These In addition, the adults of female produces two diapausing eggs at a time, encased in a saddle- diapausing eggs sink to the bot- many freshwater zooplankton shaped protective covering known tom of the lake, pond, or river cannot tolerate desiccation and as an ephippium. When the female until they receive the appropriate therefore are not capable of ac- molts, the ephippium is released cues to resume development. tively dispersing overland from and sinks to the water bottom. The cues vary among species system to system. However, and are not well understood, but many of these specialized dor- aquatic ecology. This oversight likely include changes in light and mant stages resist drying, freez- is unfortunate because they are temperature. Historically it was ing, and gut passage through often an integral part of the sys- thought that these eggs served vertebrates, thus offering a series tem, and the response of systems to carry the population through of passive dispersal options. to perturbations will be related short-term environmental catastro- Dormant propagules have been directly to the ability of an egg transported to new loca- bank to store diversity. Cur- tions by ducks and other rent research being carried out birds, wind and rain, rac- by the Center for Aquatic Ecol- coons, and insects. Humans ogy focuses on the causes and have increased the rate of consequences of these eggs in intercontinental dispersal aquatic systems. Understanding when mud containing the the role of dormancy is essential diapausing eggs is intro- in making long-term predictions duced through ballast water about ecosystem responses to an- exchanges or ﬁ sh-stocking thropogenic disturbances. Long- Aquatic Ecology practices. These human- lived dormant eggs can affect caused dispersal vectors are the ecology and evolution of the likely responsible for the populations that produce them. Photo by Carla Cáceres, INHS Center for introduction of at least two Therefore, to fully understand the exotic zooplankters into Il- dynamics of the planktonic stage linois waterways. The pre- we must consider its ties to the dacious Bythotrephes ced- Adult Daphnia galeata dormant stage as well. phes, such as the winter or the dry mendotae (left) and erstroemi, which entered Lake Carla E. Cáceres, Center for Aquatic Daphnia pulicaria, season. However, recent studies Michigan in the mid- 1980s, has both with subitaneous have indicated that some diapaus- been implicated in changes in the Ecology eggs. The Daphnia ing eggs are capable of remain- Lake Michigan food web. More pulicaria is about 3mm ing viable in the mud for over a recently, the suspension feed- long. century. This longevity increases ing Daphnia lumholtzi has been the life span of these organisms found in the Illinois River and from weeks or months to years several Illinois reservoirs. or even decades. In addition to The role of diapausing egg being extremely long-lived, dia- banks is rarely considered in

2 Wetland Bird Conservation in Northeastern Illinois

Half of the 42 bird species listed (IDNR) and the U.S. Fish and among sites from year to year, both sampling design as endangered or threatened Wildlife Service, is conducting a making it diffi cult to predict the and logistics. To in Illinois nest exclusively in long-term study of wetlands that habitat requirements of the popu- overcome the logisti- wetlands. This relatively high is designed to provide accurate lation in the long term. In order cal problem volun- proportion of wetland species is estimates of the regional abun- to better understand the move- teers will be used to largely due to the loss of much of dance and distribution of wetland ments of these birds INHS and gather foraging data the state’s wetland habitat since birds. IDNR scientists are color mark- throughout the region. the early 1800s. Continuing de- Study sites are systematically ing large numbers of individuals. This summer, trained searched for nests The goals of this study are to: volunteers from the and the fate of all 1. quantify the reproductive Bird Conservation nests recorded. success of Yellow-headed Network will collect Characteristics Blackbirds, preliminary data at 12 (physical and fl oral) 2. assess habitat characteristics marshes in Lake and of marshes and nest that favor Yellow-headed McHenry counties. sites are also re- Blackbirds, and Information gathered corded. During the 3. assess site fi delity and dis- this year will be used 1997 fi eld season a persal in the area. to design a long-term team of 5 research- monitoring program ers working in 10 III. Use of foraging habitat by scheduled to begin in Photo by Michael Jeffords, wetlands located herons and egrets in northeast- 1999.

INHS Center for Economic Entomology and monitored 450 ern Illinois. nests of 13 species. One of the most diffi cult David Enstrom, Charles In the coming fi eld problems involving wetland bird Paine, Mike Ward, and A Great Egret, one of the colonial wetland- season the effort conservation in rapidly develop- James Herkert, Center for dependent birds in Illinois being studied by will grow to 11 workers ing areas is the protection of Biodiversity INHS scientists. monitoring 90 wetlands. foraging areas required by colo- The goals of this project nial waterbirds (e.g., herons and velopment, which threatens our are to: egrets). These species nest in remaining wetlands and promises 1. develop estimates of the dis- tight aggregations in small areas further declines for wetland birds, tribution and abundance of but forage up to 20 km away in is particularly acute in northeast- wetland-dependent birds on the surrounding wetlands. In or- ern Illinois where, in spite of the a regional scale, der to protect the foraging habitat loss of much of the presettlement 2. assess the health of wetland of these species it is necessary to wetland acreage, signifi cant popu- bird populations in the re- have accurate estimates of habi- lations of wetland birds persist. gion, tat utilization on a large scale. A major impediment for 3. evaluate the effects of habitat Gathering these data presents wetland bird conservation is the characteristics on nest pro- signifi cant problems concerning lack of information regarding the ductivity, and population dynamics and habitat 4. develop conservation priori- requirements for these species. ties for wetland birds in the Here we outline three projects region. that aim to improve our knowl- edge of wetland-dependent bird II. The population dynamics of species in northeastern Illinois. Yellow-headed Blackbirds in northeastern Illinois. I. Abundance and nesting pro- IDNR Natural Heritage biolo- ductivity of wetland-dependent gists have recorded the presence birds in northeastern Illinois. and absence of Yellow-headed Photo by Michael Jeffords, Dr. C.R. Paine of the Max Blackbirds at marshes in north-

McGraw Wildlife Foundation, eastern Illinois over the past 20 INHS Center for Economic Entomology in cooperation with the Illinois years. These data indicate that Department of Natural Resources Yellow-headed Blackbirds move A typical wetland in northeastern Illinois that serves as habitat for many species of animals.

3 Illinois Earthworms: Indicators of Soil Health?

Soil is one of Illinois' most valu- important members of the soil soil type but different manage- able natural resources. It supports community because they can be ment systems: 1) no-till corn- biomass production the most abundant invertebrates soybean rotation, 2) conventional (including food, fi - by weight, reaching up to 1,000 tillage corn-soybean rotation, ber, and energy); it lbs live weight per acre in some and 3) conventional tillage with a fi lters, buffers, and agricultural soils, and even more longer rotation including a peren- transforms environ- in unmanaged soils. Further- nial hay. We collected samples mental pollutants; more, because of the ability of from cornfi elds on each farm and it provides a earthworms to redistribute large (nine samples per fi eld) as well as biological habitat amounts of soil and organic mat- from uncultivated grassy border and genetic reserve ter (roughly as much as their areas of each fi eld (three samples for a vast number of own body weight each day), they per fi eld). For each sample, we organisms. The abil- may shape the rest of the soil dug soil from a pit 12 inches x 16 ity of soil to perform community and important eco- inches x 8 inches deep. We hand these functions is system processes such as water sorted the earthworms from each called soil quality or infi ltration, nutrient cycling, and sample, then counted, weighed, soil health. In recent decomposition. In Illinois, about and (in the case of adults) pre- years, concerns about 35 species of earthworms have served them for identifi cation. the sustainability of been reported. Of these, roughly We kept juvenile worms in lab food production and half are native species about culture for identifi cation when the off-site impacts which we know very little. The they matured. of soil degradation remainder are mostly European Because of our method of have given impetus species that probably came to sampling, we collected mostly to efforts to develop North America in soil used for endogeic earthworms—worms Photo by Ed Zaborski, INHS Center for Economic Entomology objective criteria for ship ballast or on the roots of that tunnel back and forth through assessing and moni- nursery stock. the topsoil and feed on buried toring soil quality. Although the initial focus in developing soil quality criteria has been on chemical A nightcrawler (Lum- bricus terrestris) in its and physical properties, scientists permanent vertical recognize that many important burrow. functions of soil, such as decomposition and nutrient cycling, are mediated by the organisms liv- for Economic Entomology

ing in soil, and that an objective, Photo by Ed Zaborski, INHS Center comprehensive assessment of soil A nightcrawler out of its burrow and crawling on pavement. quality should include biological parameters. The soil is home to a complex community of organ- During May-June 1997, as decaying organic matter and or- isms that includes bacteria, fungi, part of the Illinois Soil Qual- ganic matter-rich soil. We did not protozoa, nematodes, potworms, ity Initiative (ISQI), Survey collect anecic earthworms, such earthworms, mites, springtails, scientists sampled earthworm as the nightcrawler, Lumbricus millipedes, centipedes, and other populations on 12 Illinois farms terrestris, that form permanent arthropods, so there are many in conjunction with sampling of vertical burrows 3-9 feet down potential candidates for biological physical, chemical, and microbi- into the soil and pull plant resi- indicators of soil quality. ological properties by University dues from the soil surface into Earthworms are the largest of Illinois soil scientists. Farms their burrows to feed. and most familiar soil inverte- were clustered in groups of three The most striking observation brates in Illinois soils. They are that had similar hydrology and Continued on next page

4 we estimated an abundance of Earthworms 1.54 million worms per acre. The continued from previous page difference between in-fi eld and grassy border populations was was the difference in abundance even greater when we considered ogy of earthworms between culti- the living weight of the earth- vated fi elds and their uncultivated worms: an average of 78 pounds Photo by Ed Zaborski, INHS grassy borders. Across all farm- per acre within fi elds, with a max- Center for Economic Entomol- ing systems we estimated an aver- imum of 179 pounds per acre, and Endogeic earthworm that burrows back and forth through topsoil and helps develop soil structure. age of 148,000 worms per acre almost 30 times that weight —an within the fi elds (up to 292,000 average of 2,263 pounds per acre but they were also smaller. In earthworm species worms per acre in one fi eld) and and a maximum of 5,909 pounds contrast to the difference between may not tolerate soil almost four times as many, an per acre—in the grassy borders. fi elds and grassy borders, we disturbance; we found average of 589,000 worms per Thus, topsoil-dwelling earth- were unable to detect a difference them in the grassy acre, in the grassy border areas. worms were not only less abun- in the number or weight of top- border areas, but not In one of the grassy border areas, dant within fi elds than in borders soil-dwelling earthworms among within the fi elds. the fi elds with difdifferentferent manage- We hope to relate ment practices. our observations on What caused earthworm popula- the difference in tions to information earthworm popula- about soil physical tions between grassy and chemical charac- borders and cropped teristics and soil man- fi elds? There are agement practices. By several possible identifying factors that explanations, keep- affect the abundance ing in mind that we and structure of earth- sampled only topsoil- worm populations dwelling earthworm in agricultural soils, populations. During we hope to develop the winter, the thick biological criteria for layer of grass on the assessing and moni- soil surface in the toring the health and grassy borders may quality of agricultural afford some pro- soils in Illinois. tection to the soil; researchers have Ed Zaborski, Center for shown that bare soil Economic Entomology freezes more deeply, resulting in higher earthworm mortality. The grassy borders may also provide a more abundant, stable, and nutritious food supply to support larger populations of earthworms. Agricultural practices and chemicals may result in higher mortality of earthworms within the fi eld than occurs in uncultivated border areas. Finally, native

5 Species Spotlight “When one approaches the coun- Illinois, Passenger Pigeons were food for settlers, but until the try of Illinois, one sees during the common summer residents in the advent of market hunting (har- Passenger day, clouds of doves, a kind of north, especially along the Des vesting the birds for faraway mar- wood or wild pigeon. A thing that Plaines River. Occasionally the kets), local people had very little Pigeon may perhaps appear incredible is birds would winter in southern impact on pigeon populations. By that the sun is obscured by them; Illinois. 1840, market hunting was a major Susan Post these birds living only on the Gregariousness was highly industry. The coming of the rail- beechnuts and acorns in the for- developed in these birds, so their roads allowed rapid access to ma- ests, and are excellent in autumn; activities —fl ying, roosting, rest- jor nesting colonies and provided sometimes as many as 80 of them ing, and nesting—were done in a quick way to ship barrels of are killed with one shot.” great numbers. When they landed pigeons to the big cities. The tele- N. Bossu while voyaging up on trees they formed “crowded graph informed market hunters of the Mississippi, 1768. rows,” which caused branches nesting colony locations. Hunters to snap under their weight and would attack a colony with guns, The Passenger Pigeon, with their dung would “fall like hail.” nets, saws, and poles, intent on its small head and neck, red spar- In Illinois residents were able taking as many birds as possible. kling eyes, long tail, and plum- to witness the great migrations Although many adults were shot, of abundant Passenger Pigeons the commotion also caused nests through the state, with great to be abandoned; delectable nest- hordes fl ying overhead from lings were also part of the bounty. late March to early April. A In nearly every breeding colony single fl ock could stretch for 300 it was possible to harvest all the miles—from Chicago to St. Lou- young, and this decimation hap- is—and take 14 hours to fl y by. pened year after year. Although The Passenger Pigeon had a destruction of the forests and varied diet. Staple foods during overhunting are often given as the fall, winter, and spring were causes for the bird’s demise, the acorns, chestnuts, and beechnuts; fact that the reproductive suc- during the summer soft fruits cess of the Passenger Pigeon was

Photo from INHS image archives were eagerly sought. Their affi n- nearly nonexistent for many years ity for nut-producing trees made ultimately led to its end. Passenger Pigeons an important On March 24, 1900, the last component of the eastern decidu- wild Passenger Pigeon was killed A stuffed Passenger Pi- ous forest. Unlike chickens, these in Pike County, Ohio, leaving the geon on display at the birds never obtained food by species represented by only a few Illinois Natural History Survey. age that ranged from slatey blue scratching with feet, instead they captive individuals in zoos. Mar- on the head to grayish blue on overturned leaves and soil with tha, the last Passenger Pigeon, the back, had an air of elegance. their bills. To gather nuts they died on September 1, 1914, at the But appearances can be deceiv- would land on the outer ends of Cincinnati Zoo. ing— these now-extinct birds, oak or beech limbs, seize the nut Aldo Leopold wrote of the although beautiful, were powerful in their bill, fan backwards with Passenger Pigeon, “Yearly the fl ight machines. The Passenger their wings, pull the nut from the feathered tempest roared up, Pigeons' massive breast muscles tree, and swallow it whole. down, and across the continent were attached to a deep keel and Like the periodical cicada sucking up the laden fruits of for- their long, pointed wings allowed of North America and the wil- est and prairie, burning them in for speed as well as aerial acrobat- debeest of African plains, the a traveling blast of life.” Like a ics. Their dashing and wheeling, Passenger Pigeon’s strategy meteor that burns brightly across dipping and darting earned the for survival was overwhelming the sky for a few hours or days, bird the title of “blue meteor.” abundance. Nesting aggregations the Passenger Pigeon experienced Audubon wrote of the Passenger were so vast that local predators great success as a species before Pigeon, “When an individual is (hawks, raccoons, foxes, and its light dimmed and died when seen gliding through the woods opossums) couldn’t wipe them Martha quietly slipped from her and close to the observer, it passes out. Humans, though, were a dif- perch—its legacy only a handful like a thought, and on trying to see ferent story, and by the beginning of historical accounts and a few it again, the eye searches in vain; of the 20th century only a few stuffed birds with vacant stares. the bird is gone.” captive birds were left. Man had Passenger Pigeons were found succeeded where other predators only in eastern North America and had failed. were once the most abundant bird The arrival of great fl ocks of on earth, numbering billions. In Passenger Pigeons always meant

6 The Naturalist's Teacher’s Guide to “The Naturalist’s Apprentice” Apprentice

Color a Passenger Pigeon Passenger Pi- geon Colors You will never see a Passenger Pigeon ﬂ ying through the sky. You will never see the subtle beauty of the rust-colored chest or the bluish gray back, or catch a glimpse of the iridescent greens and pinks as the sun- light strikes the feathers on its neck. Color the Passenger Pigeon below and try to imagine what a ﬂ ock of Carolyn Nixon thousands of them must have looked like!

Answers

2 3 10 6 1 1=Black 4 9 4 2=Red 8 3=Rusty Brown 6 3 4=Dark Brown 5 7 3 5=Light Gray 10 4 6=Dark Gray 5 3 7=Blue Gray 4 8=Yellow Green 1 4 9=Pink 2 10=Tan 4 11 11=White

“The Naturalist’s Apprentice” presents educational activities for middle school students. Teachers are invited to photocopy this page for classroom use. I LLINOIS Non-Proﬁ t Org. NATURAL U. S. Postage HISTORY PAID S U RVE Y Champaign, IL 61820 Permit 75 607 East Peabody Drive, Champaign, Illinois 61820 USA

Raccoons tion rates on Zebra Finch eggs aspects of our research are show- continued from front page showed no pattern. Further, only ing that natural areas embedded about 35% of the quail eggs we in this agricultural landscape system (GPS) to pinpoint precise- attract and support high densities Illinois Natural His- set out were depredated, whereas tory Survey Reports is ly the locations from which we the total predation rate when the of a diversity of potential nest published bimonthly took our bearings and a computer- Zebra Finch eggs were included predators. Although some preda- by the Illinois Natural based geographic information reached about 75%, close to tors like raccoons may use edges History Survey, 607 system (GIS) to map our data onto the rate for natural nests at our extensively, some small mammals East Peabody Drive, Champaign, IL 61820. aerial photos, we could then plot study site. Because the quail and and snakes (which we are also Headquartered on the nightly movements and habitat fi nch eggs were together in the radio tracking) may prey on nests the campus of the use of our study animals at the same nest and we assume that far from edges. We hope to iden- University of Illinois Middle Fork. From these data, we a predator like a raccoon takes tify patterns of habitat use by dif- at Urbana-Cham- could clearly show that raccoons ferent kinds of predators, and pat- paign, the Survey is a both eggs if it fi nds a nest, those division of the Illinois and opossums used habitat edges cases where the fi nch egg was terns of nest predation in different Department of Natural extensively during their nightly eaten but the quail egg was left kinds of habitats and landscapes, Resources. activities, and were located less indicate that some other predator that may point to management frequently than expected out in was at work. For example, mice practices that could improve the open fi elds away from edges. So, and chipmunks can prey on small nesting success of songbirds. In INHS Reports is ed- does that mean we can blame edge the meantime, don’t blame it all ited by Tom Rice and eggs like fi nch eggs (and most Charlie Warwick and effects in nest predation on rac- songbird eggs), but can’t break on the raccoons. printed on recycled coons? the larger, harder quail eggs. and recyclable paper. Our experiments with artifi cial A preliminary analysis of nest Ed Heske, Dan Rosenblatt, and Julianne Design by Otto-Walker nests showed there was a moder- predation on over 1,800 natu- Newton, Center for Wildlife Ecology Communications. ate tendency for predation rates on ral songbird nests found at the the quail eggs to be lower in larger Middle Fork by other biologists fi elds, and a weak trend for preda- working on this project also did tion rates to be higher near edges, not show any clear spatial pat- as we expected. However, preda- terns relating to edges. Other