Grets Build Nests and Rear Young in Rookery
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VOLUME 3 JANUARY 1s, 19 44 NUMBER Perch Family Made American ~grets Build Nests and Up of Numerous Interesting Members Rear Young In Rookery Near Sabula By E B SPEAKER • Superintendent of F1sheries No group of fishes in Iowa is Colony Consists of held in higher esteem than the larger members of the perch fam Between 700 and ily, the walleye pike, yellow perch and sauger. Equally in teresting in this group but too 900 Individuals small to serve as food are the 16 By JAMES R HARLAN l1ttle darters, many of whtch are go1·geously colored. Reprinted From Iowa B~rd Ltfe Walleyes are found principally For at least the second succes in the larger natural lakes, the sive year American egrets ar boundary r1vers, and a number known to have made their sum of the maJor inland streams. They mer home and successfully raised spawn early m April soon after their young in an Iowa rooker) the ice disappears, depositing The colony is located in the Mis their eggs aimlessly over rock or sissippi River bottom in Jackso1 gravel bars, after which they re County about three miles abov< turn to deeper water, leavmg the the town of Sabula and a mil eggs to develop unattended and west of the river channel prope the tmy offspring to shift for For a number of years egre• thE'mse l ves. have become increasingly corr. NaturE' has provided this care mon, after havini' been almost en less family with the ability to tirely absent from the state fc deposit enormous numbers of f'ggs nearly 20 years. Undoubted] to compensate for th0 Joss which Part of the Amencan egret nests in the Sabula rookery. Several birds may be seen these egrets were first-year yount invariably follows. These losses perched in the trees, and two have been caught in mid-air by the cameraman that had come into the state fror are caused by a multiple of fac southern rookeries to fish, anc tors, including abrasive action of were not from Iowa nesting birds wind and sand, predation by fish The fact that egrets were nest es and aquatic insects, and dis Market Hunting of Waterfowl ing on Iowa's Mississippi bottor ease. The size of the eggs varies was brought to the attention o considerably in different locali the writer in a casual conversa ties and among individuals. Eggs In ~arly Days--Slaughter tlon m the latter part of Jul~ 150,000 usually average from to By JACK W MUSGROVE • 1942, with Conservation Office 160,000 to the quart and shortly duck raft continued to increase D1rector, State Museum Blll Morf, who in the company o. after fertilization double in size. in size and number, the indis Don Edlen had found the colon} The incubation period varies in The glow of the early spring tinct shape of a boat, camouflaged earlier in the year. At that time direct relation to the tempera sunset touched with red the wings with rushes, glided from the they estimated the birds to num ture of the water. In Iowa the of waterfowl mtlling over the shores. In it were two shadowy ber 1,500 individuals, includin;, eggs hatch in about 12 to 20 days. lake. As darkness approached forms, one at the bow completing great blue herons. Insomuch a~ The tiny fish, or fry as they are the number increased until the the loading of a large swivel the birds were no longer in tht called, are about 3116 inches in sky was filled with the shadowy gun, the other manning an oar colony, it was impossible to verify length. They are transparent and forms. As they settled with the that pushed the boat silently the report or visit the nests that individually are scarcely visible mass of birds already at rest on through the thick vegetation to year. However, the nesting ob to the eye. the water, the clamor of their the open water. Ahead, the raft servation of Morf and Edlen for Development is rapid, and by voices could be heard for miles. of waterfowl crowded together 1942 cannot be questioned. fall the youngsters are from Here, in their favorite resting still unalarrned, unaware of the In late J une, 1943, in the com three and a half to six or more place, they fed and bathed, and approaching doom of many of pany of Garfield Harker of Ma inches in length. Normally, they conversed with their fellows. their numbers. quoketa, the conservation office1 <Continued to Pilge 3 Column 2l Long after darkness, as the (Continued to Page 5 Column 4) (Continued to page 2, Column 1) PAGE TWO IOWA CONSERVATIONIST Iowa Conservationist This Clumsy Kid Fell Out of Bed We were immediately aware of Published Monthly by splashes m the water underneath THE IOWA STATE CO NSERVATIO N the nest trees. We assumed that COMMISSION these were droppings from the lOth & Mulberry-Des Mo1nes, Iowa young birds, however, the wnte1 JAMES R HARLAN, Editor mvestigated and found heavy F T SCHWOB, Dir&lor masses of regurgitated, partially (No Rights Reserved) digested fish. In one particula1 mstance the pellet consisted of MEMBERS OF THE COMMISSION three partially digested carp about 3 1 2 mches long and one F. J POYNEER, Cedar Rapids, Chairman green sunfish a little smaller. In J 0 LOWE Algona all the pellets subsequently ex F w MATTES Odebol t ammed carp was the pnnc1pal MRS ADDISON PARKER Des Mo1nes component. E B. GAUNITZ Lansing There were more than 50 nests R E STEWART Ottumwa on the ground or in the water un A. s WORKMAN Glenwood der the trees Some appeared to CIRCULATION THIS ISSUE - 21 47(' have been blown from the trees, Subscnpt1on Rate 40c per year but the maJority Wl.re still at Subscnptions received at Conservation tached to the dead limbs rn \\'hich Comm1SS1on, lOth and Mulberry, Des Momes, they were origmally placed many Iowa Send co1n, check or money order feet above and had come down Conservation Commission almost mtact. There were no egg .Milita ry Service Donor Roll fragments or remains of young m the vJcmJty, possibl} because of the numerous raccoon that fre ..,- ~ ------.. ~ ----- i r·r.:;; -- • ...____z.. -;- ~ 5"'r1n quent the area. ~ ~ --- __-=!' It was estimated that the col r. A.(XA'JO[~z; * " 1-.'AH~'• A-;' ony con tamed some 250 intact * B RllY. Jl.[b. M * ~.101:.N. Tl~ OS egret nests This figure was ar * !). JQ <.SO'J, ~ * VEil ROB T rived at by counting the nests in * " sn.r.sr:J c * c~oR. JAS * L.OL&Y, >lUBtQ~ * J~RSOtl, i) about one-th1rd of the area. The ! , * ~"DOPER. ROBT * .;,IME"'SON,l-1 nesting area itself was made up * JOPE;( \\lisa-* )STROM ~AE of some 40 trees covering approxi * F'A2>ER. LEST£~ * LYE. .EDWARD mately two acres The nests were * FIN;t... LAV£R"l * STARR,f"RAtl ~ placed for the most part m ex *r o:~:.JGEil.VW * ;:.TEMPEL £. * !':E. R CUARO * rrLU[Aivl D. ceedingly tall trees, w1th the low * l<t.V($ LERO'i* , E£NIOY ROBT est nests being approximately 50 * cP.AESING, 14 * Wl~ALEN.JOI1N feet from the ground, some bemg * ... R\:~Y.WA ...' * • LDE.MILTO:J in the tiptops more than 80 feet. * u0Sf.,J0H'. * '"' LSON, OO'J Although the young were about * ~ >f"FMAN, (J * {0\JNul'>LOOD. M ( * t<OFFMAN, ~~ * .Y.lllN5QN.11AQOLD.C ready to leave the nests, more * < :~£':>, OA' D* .JJTY AL&(QT than 50 per cent were still occu * v'IES oc,, * '' )R.F.WJ pied w1 th from two to four young. · ~ 5'0'l,TAfLOR It 1s the author's observatiOn that * AGO. rt.RL \Wd more than 60 per cent of the live * -l '~50N W A. An Amencan egret, almost fully grown, that tumbled ou t of its nest high up in a deaci \'".::01 nests were occupied by American * ';AY~!E t ottonwood - Photo by Herb Schwartz * ~ • ST£A. G(O egrets, the remamdcr by great is some five mlles wide at this the trees. It is in this eerie vast blue herons. No other nesting pomt ness that the egrets chose their birds were observed; however, Prior to the establishment of housekeepmg sites and built their Speaker identified two nests of the nme-foot channel, the bottom rookery. the black-crowned mght heron Egrets was mtersected by numerous The nests are built m a cluster the week before. <Cont1nued from Page One) "chutes", small streams of run of g1ant dead cottonwood trees, The author estimates that the m charge of Jackson Coun ly, the ning water which break away for the most part standing in the probable number of Amencan author searched the nver bot from the parent river upstream shallow waters of one of the new egrets in this group 1s from 700 toms for the colony. The nver and wmd through the lowlands. "lakes". to 900 individuals. was about five feet above normal occasionally flattening out into As our party stepped out of the While our party was t~ king stage, and many of the landmarks ''lakes", then wmding across the boat onto a narrow strip of wet photographs, the b1rds were needed to gUide a party mto the flood plam as fancy dictates to ground that separated us some greatly agitated and continued to almost impenetrable b o t toms reJOin the M1ssissipp1 farther 200 feet from the edge of the regurgitate fish remams, the later we1 e missmg. Although numer downstream. rookery, the hollow, discordant pellets being more nearly digest ous Amencan egrets were ob With the bUilding of the dams clamor of the young birds added ed than the ones first expelled.