A partially manufactured egg inside a 3D printer
图片来源：Miri Dainson和Robert Pecchia
New research that studied the benefits of using 3D printing to see how birds reject eggs has been published in thePeerj Journal。Brood parasites try to slip their eggs into other bird’s nests. However, birds have the ability to identify and reject these eggs.
Researchers used artificial eggs made out of wood, plaster and other materials in studies prior to using 3D printers. However, they had significant limitations.
育雏的寄生虫已经成功地将卵偷偷溜进了鸟类的巢中，寄主鸟养了这些小鸡，认为它们是自己的。这通常会影响他们自己的小鸡的饲养。
An evolutionary arms race has taken place in certain species, and host parents seem to have improved their ability to identify and reject eggs that are not theirs. They make use of cues such as the size, pattern, color and shape of the intruder egg. However, the brood parasites have improved their ability in producing eggs that mimic those of the host species.
Ornithologists have been studying this phenomenon for a long time to find out the manner in which birds identify impostor eggs. They added artificial eggs into nests and studied the reaction of the parent birds.
Egg Lapse
视频1：有关打印3D模型鸡蛋的及时视频，
Video credit: Hunter College, CUNY Communication Office / YouTube
美国罗宾拒绝3D模型鸡蛋
Video 2: For a video of a robin rejecting a 3D model egg (Supplemental File 1 from the article),
Video credit: Mark Hauber / YouTube
但是，很难使用诸如par粉，木材或塑料等材料模仿原始鸡蛋的假鸡蛋。亚博网站下载这些人造鸡蛋很难准确复制，并且需要很长时间才能产生它们。此外，人为错误也会影响其制造。除此之外，还需要准确的复制来确认其他研究人员的发现。
In order to overcome these restrictions, the researchers used 3D printers to create digital egg models of a North American brood parasite bird – the Brown-headed Cowbirds. 3D printing technology allowed the researchers to create hollow eggs. These eggs could then be filled with gel or water, so that their thermodynamic properties and weight matched those of the real eggs.
The researchers painted the 3D printed eggs with blue-green color so that they matched real eggs of American robins, and in beige color to match the real eggs of cowbirds. These eggs were then slipped into robin nests, and the reaction of the parent birds was observed for six days. All of the blue-green eggs were accepted by the robins. However, 79% of the beige color eggs were rejected. The results of this study were similar to results obtained in earlier studies that used artificial plaster eggs, created using traditional methods.
Hosts of brood parasites vary widely in how they respond to parasitic eggs, and this raises lots of cool questions about egg mimicry, the visual system of birds, the ability to count, cognitive rules about similarity, and the biomechanics of picking things up.
Professor Don Dearborn
Chair of the Biology Department and Brood Parasitism Expert
Bates College
However, 3D-printed eggs can be reproduced to specific shapes and sizes, and with less variance. Furthermore, the digital models can be shared, which would allow replication of the experiments by other researchers without a reduction in accuracy or confidence in results.
“几十年来，解决这些问题意味着要制作自己的假鸡蛋 - 我们都发现这是缓慢，不确定和令人沮丧的。这项研究使用3D打印来进行更细微和可重复的卵子制作过程，这反过来允许关于宿主 - 寄生虫共同进化的更精致的实验。”没有参与3D印刷研究的唐·迪尔伯恩教授说。"I'm also hopeful that this method can be extended to making thin-shelled, puncturable eggs, which would overcome another one of the constraints on these kinds of behavioral experiments."
"3D printing technology is not just in our future -- it has already revolutionized medical and basic sciences,"said Prof. Mark Hauber, an animal behaviorist at Hunter College of the City University of New York, the study's senior author.“现在，它进入了野生鸟类的世界，可以在世界范围内进行标准化的鸡蛋拒绝实验。”