referring first to fig1 - 4 , the preferred embodiment of the bird feeder 10 of the present invention will be shown in its completed and assembled form . the feeder is preferably formed by a blow molding process , which will be described later . any suitable uv stabilized plastic material may be used , such as a transparent pvc . the feeder 10 includes a hollow tubular body 11 , and integral lower end cap 12 and a removable upper end cap 13 . the upper end cap 13 is preferably demountably attached to the tubular body 11 by mating screw threads comprising an outer screw thread pattern 14 on the upper end of the tubular body and an inner screw thread pattern 15 on the lower end of the upper end cap 13 . the thread patterns 14 and 15 are formed in the molding process to be described below . the upper end cap 15 is also provided with an axial through hole 16 to accommodate attachment of a hanging device , such as a cord or wire 17 . the tubular body 11 includes a series of horizontally aligned hole pairs 18 , each pair adapted to receive a small diameter tube or rod 20 which is long enough to extend outwardly of the tubular body to form a bird perch on either side of the body . a pair of seed holes 21 is formed vertically above each perch hole pair 18 and may be suitably sized to accommodate different types of bird seed . as shown in fig1 - 3 , vertically adjacent perch rods 20 are offset by 90 °, such that in the particular feeder shown , the upper and lower perch rods are parallel to one another and the intermediate perch rod is perpendicular thereto . referring also to fig8 the lower end of the tubular body 11 , just above the lowermost hole pair 18 is provided with a pair of integrally molded annular ribs 22 formed to protrude radially inwardly . the ribs 22 are vertically spaced to define therebetween an annular groove 23 . a small circular disc 24 of plastic or other suitable material is inserted into the open upper end of the tubular body 11 and allowed to drop and rest upon the upper annular rib 22 , as best seen in fig1 and 8 . the disc 24 supports the column of seed which fills the feeder and prevents seed , seed particles and dirt from entering the lower end of the tubular body and the hollow interior of the lower end cap 12 where it is wasted and accumulates and is difficult to clean out . alternately , the upper annular rib 22 may be formed of a somewhat different shape including , for example , downwardly inclined surface portions , whereby the disc 24 could be forced downwardly past the upper annular rib and to snap into the annular groove 23 above the lower rib . in this manner , the disc 24 would be held more securely in place . in lieu of the annular ribs 22 , integrally molded , circumferentially spaced bosses could also be used to support the disc . referring also to fig5 - 7 , the bird feeder 10 of the preferred embodiment is made from a unitary blow molded enclosure 25 , the upper portion of which is shown in fig5 . the lower portion of the unitary enclosure 25 is as shown in the preceding drawings and includes the annular ribs 22 molded in the lower end of the tubular body and the integrally molded lower end cap 12 . the as - molded enclosure 25 includes an annular sleeve 26 which separates the upper end cap 13 from the tubular body 11 . the sleeve 26 is secured to the lower edge of the inner thread pattern 15 on the upper end cap along an annular seam 27 . similarly , the annular sleeve 26 is secured to the upper edge of the outer screw thread pattern 14 on the upper end of the tubular body by an integral annular seam 28 , as best seen in fig6 . the body of the sleeve 26 , between the upper and lower seams 27 and 28 , is formed with a pair of large circular ribs 29 , but the shape of the sleeve is not particularly important . the axial through hole 16 in the upper end cap 13 is formed in the blow molding process by the small tube through which gas is fed into the parison from which the enclosure is blow molded . after the enclosure 25 has been formed , the sleeve 26 is cut away along both the upper seam 27 and the lower seam 28 , leaving the separated upper end cap 13 which may be threaded onto the upper end of the tubular body 11 to close the bird feeder 10 as shown in fig7 . in an alternate embodiment , the unitary blow molded enclosure may be formed with a second annular sleeve ( not shown ) similar to the upper annular sleeve 26 to initially separate the lower end cap 12 from the lower end of the tubular body 11 . thus , as shown in fig1 and 12 , a modified lower end cap 30 is formed with an integral outer thread pattern 31 and a modified tubular body 32 includes a molded inner thread pattern 33 . when the annular sleeve is cut away ( in the same manner as the upper annular sleeve 26 previously described ), the modified lower end cap 30 may be threaded into the lower end of the modified tubular body 32 , as shown in fig1 . in fig1 , the threaded upper end 14 of a previously described tubular body 11 or the threaded upper end of a modified tubular body 32 may also be threaded into the lower end of the modified tubular body 32 to provide an extended length bird feeder . if desired , of course , a slightly modified bird feeder could be made from the blow molded enclosure 25 of the preferred embodiment ( fig5 ) by inverting the same such that the removable end cap is the lower end cap 12 and the upper end cap 13 is formed to remain integral with the tubular body 11 . the modified feeder would have to be inverted for filling , but would otherwise be made and assembled in the same manner previously described . instead of the threaded interconnections 14 and 15 or 31 and 33 , the removable end cap 13 or 30 and adjacent end of the tubular body could be molded to include means for providing a snap fit connection therebetween . for example , as shown in fig2 the cylindrical surface of the end cap 13 could be provided with a number of integral tabs 49 which project radially inwardly to cooperate with a mating series of grooves 59 formed in the upper end of the tubular body and also projecting radially inwardly . as the cap is pushed axially onto the upper end of the tubular body 11 , the tabs would snap into the grooves 59 as a result of the inherent flexibility of the plastic material , which may have a thickness of , for example , 0 . 030 inch ( 0 . 76 mm ). a further embodiment of the invention is shown in fig9 and 10 . the tubular body 11 may be formed in the blow molding process with indented portions or grooves 34 . each groove 34 is defined by a curved upper surface 35 and a flat lower surface 36 which are integrally joined at their radially inner edges along a curved edge 39 . the lower surface 36 may be molded with a scored or otherwise weakened knock - out portion which , when removed after molding , provides a seed port opening 38 . alternately , as shown , the entire flat surface 36 may be cut out , along the curved inner edge 39 and a continuous circular edge 37 . the downwardly inclined curved upper surface 35 provides a deflector hood so that seeds poured into the upper end of the tubular body or the descending column of seeds consumed by birds will not pass out of the seed port openings 38 . although the various embodiments of the subject invention have been described to include a cylindrical tubular body 11 , it should be understood that tubular bodies of any cross sectional shape may be utilized , including square , triangular , oblong and other shapes . all such shapes may be readily provided in the blow molded construction and using the blow molding method described . similarly , the diameter of the tubular body 11 , in any of various cross sectional shapes , may be made as large as desired . the embodiment shown in fig1 is similar to the fig5 embodiment , except that the fig1 bird feeder 50 is molded without an integral end cap on one end . more particularly , the feeder 50 includes a tubular body 51 which is integrally joined to a lower end cap 52 by an annular sleeve 26 which may be identical to that shown in fig5 and 6 . thus , the tubular body 51 includes an outer screw thread pattern 54 and the lower end cap 52 includes an inner screw thread pattern 55 . after the feeder 50 is blow molded , the annular sleeve 26 is separated in two places to form a parting seam 27 along the end of the lower end cap and a parting lip 28 at the end of the tubular body . the lower end cap 52 may be threaded onto the lower end of the tubular body 51 , as previously described with the embodiment of fig5 - 7 . if desired , however , the bird feeder 50 may be used as molded without cutting away the annular sleeve 26 . the upper end of the tubular body 51 includes only an integral outer screw thread pattern 56 defining the upper opening in the tubular body and the point of attachment of a separately molded end cap , such as those to be described with respect to fig1 and 15 . the open upper end of the tubular body also provides the opening for the gas used in the blow molding process . referring now to fig1 and 15 , there are shown two differently shaped end caps 57 and 58 , either of which may be utilized as the upper end cap for the bird feeder 50 of fig1 , instead for example of an integrally molded separable end cap 52 . the smaller end cap 57 includes an inverted cup - shaped body 60 having an inner thread pattern 61 for permitting it to be screwed onto the outer screw thread pattern 56 on the upper end of the tubular body . the cap also includes an integral downwardly extending conical hood 62 . the larger end cap 58 of fig1 also includes a cup - shaped body 63 which is somewhat deeper than the body 63 of the fig1 cap . the body 63 includes an inner thread pattern 64 , also adapted to mate with the screw thread pattern 56 at the top of the tubular body 51 . a somewhat larger integral hood 65 is provided on the larger end cap and provides protection against rain and snow entering the seed ports . both end caps 57 and 58 may be made of plastic by injection molding or could be made of metal or other material , if desired . each of the end caps 57 and 58 includes a central through hole 66 , located similarly as the axial through hole 16 in the end cap 13 previously described , for the purpose of attaching a feeder hanger . the hanger preferably comprises a relatively rigid length of wire 67 which is knotted or otherwise bent at its lower end 68 to secure the hanger in place as the wire is inserted upwardly through the hole 66 in the end cap . by connecting the hanger in this way , the feed tube can be unscrewed from the cap without disturbing the attachment of the cap and hanger wire to the feeder support structure . on the outside , a flexible washer 70 is slipped onto the wire 67 and down into contact with the top of the end cap to provide a water tight seal . one preferable form of the wire hanger 67 is 18 gauge solid copper wire covered with a plastic coating . the washer 70 is preferably a neoprene washer . braided or twisted cord materials may also be used as a hanger . in fig1 and 17 , there is shown another embodiment of a tubular body 71 which provides a much greater adaptability for the connection of accessory pieces to vary the size , capacity and functionality of the bird feeder in which it is used . the main portion of the body 71 may include conventional seed holes and opposite hole pairs for a perch rod , as previously described with respect to other embodiments . the upper end of the tubular body 71 is provided with an outer screw thread pattern which may be identical to the pattern 14 formed in the tubular body 11 of fig5 - 7 or the upper thread pattern 56 formed in the tubular body 51 of fig1 . correspondingly , any of end caps 13 , 57 or 58 may be utilized therewith to provide an upper closure for a bird feeder utilizing tubular body 71 . the lower end of the tubular body 71 is provided with an inside thread pattern 75 and an outside thread pattern 76 . the outside thread pattern 76 may be similar to the outer screw thread pattern 54 in the tubular body 51 of fig1 and formed in a similar manner . thus , the outside thread pattern 76 may be adapted to accommodate an integrally formed and subsequently separated lower end cap 52 of the fig1 embodiment or some other type of separately molded threaded end cap . referring to fig1 , the outside thread pattern 76 may also be utilized to accommodate attachment of a seed tray 77 . this seed tray is preferably made of an injection molded construction and includes a shallow lower tray portion 78 which surrounds a central upwardly extending tubular sleeve portion 80 . the sleeve portion includes an inner thread pattern 81 allowing the tray 77 to be threaded onto the outside thread pattern 76 on the end of the tubular body 71 . the interior of the tubular sleeve 81 is completely open to allow independent access to the inside thread pattern 75 after the seed tray 77 has been attached . the inside thread pattern 75 is designed to accommodate attachment of another tubular body , such as by means of the outer screw thread pattern 56 on the upper end of tubular body 51 in fig1 . in this manner , an extended length bird feeder may be provided , similarly to the embodiment described above and shown in fig1 . alternately , the inside thread pattern 75 may 20 be utilized to accommodate a seed tray 82 shown in fig1 . seed tray 82 also includes a lower tray portion 83 and an integral upstanding tubular sleeve 84 . the tubular sleeve is provided with an outside thread pattern 85 adapted to cooperate with and provide connection to the inside thread pattern 75 in the tubular body 71 . the top of the tubular sleeve 84 includes an integral closure face 86 to enclose the bottom of the tubular body and retain the seeds therein . the closure face 86 may include a series of moisture relief holes 87 to help dispel any moisture which may accumulate in the tubular body . the tray portion 83 includes a series of drain holes 88 to drain rain water which might otherwise accumulate in the tray . similar drain holes are provided in the seed tray 77 of fig1 . an integral post sleeve 89 may be located coaxially within the tubular sleeve 84 and depend downwardly from its connection with the closure face 86 . the bottom of the post sleeve 89 is open to allow the tray and the attached feeder assembly to be mounted on a suitable supporting post . preferably , a series of circumferentially spaced reinforcing ribs 90 connects the upper end of the post sleeve 89 to the underside of the closure face 86 .
a tubular plastic bird feeder is made from a unitary blow molded enclosure which includes engageable thread patterns on one end cap and the adjacent end of the tubular body which are separated in molding by an integral annular sleeve . the sleeve is cut away circumferentially at both ends from the as - molded enclosure leaving a separated end cap which may be threaded onto the end of the tubular body . similar integrally molded thread patterns may be formed on the other end of the unitary enclosure to provide either another removable end cap or the facility to thread another tubular body onto the end of the first tubular body to provide an extended length feeder . one embodiment includes a circular barrier disc supported in the tubular body below the lowermost seed holes to prevent seed , and other particles from accumulating in the inaccessible lower end of the feeder . in lieu of conventional seed holes cut , punched or otherwise formed in the tubular body , the body may be formed in the blow molding process to include angled seed ports with protective deflector hoods . another embodiment includes internal and external thread patterns on one end of the tubular body to accommodate either of two seed tray constructions .