Former Vice President Joe Biden continues to lead the pack of presidential hopefuls among Iowa Democrats, but the latest CNN/Des Moines Register/Mediacom poll shows his support is slipping as a few candidates are making big gains. Overall, 24 percent say they back Biden, while second place is a virtual tie between Vermont Sen. Bernie Sanders with 16 percent, Massachusetts Sen. Elizabeth Warren with 15 percent and South Bend, Indiana Mayor Pete Buttigieg with 14 percent.

None of the other presidential hopefuls managed to break the double digits in the poll that takes into account those who plan to caucus the traditional way and those who are planning to caucus virtually. California Sen. Kamala Harris is the one who comes the closest with 7 percent support while Minnesota Sen. Amy Klobuchar and former Texas Congressman Beto O’Rourke are at 2 percent. Seven candidates have 1 percent support and nine don’t have any backing. New York City Mayor Bill de Blasio and Miramar, Florida, Mayor Wayne Messam had particularly dismal showings in the poll as not a single respondent listed them as either their first or second choice for president.

While Biden remains clearly in the lead there are lots of warning signs for the former vice president. Chief among them is that his support appears to be clearly declining as the race progresses. In December Biden was leading with 32 percent, compared to 19 percent for Sanders while in March support for Biden was at 27 percent while Sanders had 25 percent. That downward trajectory is quite the contrast to Warren, whose support was at 8 percent in December and 9 percent in March and has since soared to 15 percent. Buttigieg has seen an even bigger surge as he only had 1 percent support in March and is now at 14 percent.

Biden supporters are also less enthusiastic. Among those who list Biden as their first choice for president, 29 percent say they are “extremely enthusiastic,” compared to 39 percent for those who make another candidate. Biden also has the biggest name recognition in the field meaning he has less room to grow.

Appearing on ABC’s This Week, O’Rourke dismissed his weak showing in the poll. “I don’t know that this many months out from the caucuses in Iowa these polls really indicate what our prospects are,” O’Rourke said. “If I relied on polls, in any race I’ve run, I never would have served in the U.S. Congress, never would have taken on Ted Cruz. Never would have been able to lead the largest grassroots effort in the state of Texas.” For his part, Sanders said that the large number of candidates meant that it’s unlikely any presidential hopeful will get to 50 percent support in Iowa.

Beto O'Rourke: "I don't know that this many months out from the caucuses in Iowa, that these polls really indicate what our prospects are. If I relied on polls in any race that I've run, I never would have been able to serve in the United States Congress" https://t.co/5F8Y5mHv0t pic.twitter.com/MZbkhNubI2 — This Week (@ThisWeekABC) June 9, 2019